Power operated rotary knife

ABSTRACT

A power operated rotary knife including an annular rotary knife blade supported for rotation in a blade housing. The rotary knife blade including a body and a blade section extending from the body. The body includes an outer wall including an arcuate surface having an upper region extending from a first upper end portion to a second intermediate portion and a lower region extending from the second intermediate portion to a third lower end portion. A plurality of gear teeth extend downwardly from the upper end of the body, each of the plurality of gear teeth including an outer peripheral face forming a portion of the upper region of the arcuate surface of the outer wall. The body outer wall includes a bearing surface having a lower bearing face in the lower region of the arcuate surface and an upper hearing face in the upper region of the arcuate surface.

TECHNICAL FIELD

The present disclosure relates to a hand held, power operated rotaryknife.

BACKGROUND

Hand held, power operated rotary knives are widely used in meatprocessing facilities for meat cutting and trimming operations. Poweroperated rotary knives also have application in a variety of otherindustries where cutting and/or trimming operations need to be performedquickly and with less effort than would be the case if traditionalmanual cutting or trimming tools were used, e.g., long knives, scissors,nippers, etc. By way of example, power operated rotary knives may beeffectively utilized for such diverse tasks as tissue harvesting orrecovery, debriding/removal of skin tissue, bone tissue, tendon/ligamentharvesting from human or animal tissue donors for medical purposes.Power operated rotary knives may also be used for taxidermy and forcutting and trimming of elastomeric or urethane foam for a variety ofapplications including vehicle seats.

Power operated rotary knives typically include a handle assembly and ahead assembly attachable to the handle assembly. The head assemblyincludes an annular blade housing and an annular rotary knife bladesupported for rotation by the blade housing. The annular rotary blade ofconventional power operated rotary knives is typically rotated by adrive assembly which include a flexible shaft drive assembly extendingthrough an opening in the handle assembly. The shaft drive assemblyengages and rotates a pinion gear supported by the head assembly. Theflexible shaft drive assembly includes a stationary outer sheath and arotatable interior drive shaft which is driven by a pneumatic orelectric motor. Gear teeth of the pinion gear engage mating gear teethformed on an upper surface of the rotary knife blade.

Upon rotation of the pinion gear by the drive shaft of the flexibleshaft drive assembly, the annular rotary blade rotates within the bladehousing at a high RPM, on the order of 900-1900 RPM, depending on thestructure and characteristics of the drive assembly including the motor,the shaft drive assembly, and a diameter and the number of gear teethformed on the rotary knife blade. Power operated rotary knives aredisclosed in U.S. Pat. No. 6,354,949 to Baris et al., U.S. Pat. No.6,751,872 to Whited et al., U.S. Pat. No. 6,769,184 to Whited, U.S. Pat.No. 6,978,548 to Whited et al., U.S. Pat. No. 8,448,340 to Whited, andU.S. Pat. No. 8,726,524 to Whited et al., all of which are assigned tothe assignee of the present invention and all of which are incorporatedherein in their respective entireties by reference.

SUMMARY

In one aspect, the present disclosure relates an annular rotary knifeblade for rotation about a central axis of rotation in a power operatedrotary knife, the annular rotary knife blade comprising: a body and ablade section extending from the body, the body and the blade sectionbeing radially centered about the central axis of rotation; the bodyincluding a first end and a second end spaced axially below the firstend and an inner wall and an outer wall spaced radially apart, the outerwall of the body including an arcuate surface extending from an upperend portion through an intermediate portion to a lower end portion, theupper end portion of the arcuate surface being axially closer to thefirst end of the body than the intermediate portion and the lower endportion and the lower end portion of the arcuate surface being axiallycloser to the second end of the body than the intermediate portion andthe upper end portion, the arcuate surface being convex radially outwardwith respect to the central axis of rotation, the arcuate surfaceincluding an upper region extending between the upper end portion andthe intermediate portion and a lower region extending between theintermediate portion to the lower end portion; the body furtherincluding a driven gear having an upper end and an axially spaced apartlower end and comprising a plurality of gear teeth, the plurality ofgear teeth of the driven gear extending axially downwardly from thefirst end of the body and extending radially through the outer wall ofthe body, the plurality of gear teeth including outer surfacescomprising at least a part of the upper region of the arcuate surface;the outer wall of the body further including a bearing surface forrotatably supporting the annular rotary knife blade for rotation aboutthe central axis of rotation, the bearing surface including an upperbearing face In the upper region of the arcuate surface and a lowerbearing face in the lower region of the arcuate surface, the outersurfaces of the plurality of gear teeth comprising at least a part ofthe upper bearing face of the bearing surface; and the blade sectionextending from the second end of the body.

In another aspect, the present disclosure relates to an annular rotaryknife blade for rotation about a central axis of rotation in a poweroperated rotary knife, the annular rotary knife blade comprising: a bodyand a blade section extending from the body, the body and the bladesection being radially centered about the central axis of rotation; thebody including a first end and a second end spaced axially below thefirst end and an inner wall and an outer wall spaced radially apart, theouter wall of the body including an arcuate surface extending from anupper end portion through an intermediate portion to a lower endportion, the upper end portion of the arcuate surface being axiallycloser to the first end of the body than the intermediate portion andthe lower end portion and the lower end portion of the arcuate surfacebeing axially closer to the second end of the body than the intermediateportion and first upper end portion, the arcuate surface being convexradially outward with respect to the central axis of rotation, thearcuate surface including an upper region extending between the upperend portion and the intermediate portion and a lower region extendingbetween the intermediate portion and the lower end portion; the bodyfurther including a driven gear having an upper end and an axiallyspaced apart lower end and comprising a plurality of gear teeth, theplurality of gear teeth of the driven gear extending axially downwardlyfrom the first end of the body and extending radially through the outerwall of the body, each of the plurality of gear teeth including an outersurface, the plurality of gear teeth including outer surfaces comprisingat least a part of the upper region of the arcuate surface and at leasta part of the lower region of the arcuate surface; the outer wall of thebody further including a bearing surface for rotatably supporting theannular rotary knife blade for rotation about the central axis ofrotation, the bearing surface including an upper bearing face in theupper region of the arcuate surface and a lower bearing face in thelower region of the arcuate surface, the outer surfaces of the pluralityof gear teeth comprising at least a part of the upper bearing face ofthe bearing surface and at least a part of the lower bearing face of thebearing surface; and the blade section extending from the second end ofthe body.

In another aspect, the present invention relates to an annular rotaryknife blade for rotation about a central axis of rotation in a poweroperated rotary knife, the annular rotary knife blade comprising: a bodyand a blade section extending from the body, the body and the bladesection being radially centered about the central axis of rotation; thebody including a first end and a second end spaced axially below thefirst end and an inner wall and an outer wall spaced radially apart, theouter wall of the body including a first arcuate surface convex radiallyoutward with respect to the central axis of rotation and extending froman upper end portion through an intermediate portion defining a radiallyoutermost extent of the body to a lower end portion, the upper endportion of the first arcuate surface being axially closer to the firstend of the body than the intermediate portion and the lower end portionand the lower end portion of the first arcuate surface being axiallycloser to the second end of the body than the intermediate portion andthe upper end portion, the first arcuate surface including an upperregion extending between the upper end portion and the intermediateportion and a lower region extending between the intermediate portionand the lower end portion; the outer wall of the body further includinga bearing race concave radially inward with respect to the central axisof rotation, the bearing race being closer to the second end of the bodythan the first arcuate surface and extending from an upper end portionthrough an intermediate portion to a lower end portion, the upper endportion of the bearing race being axially closer to the first end of thebody than the intermediate portion and the lower end portion and thelower end portion of the bearing race being axially closer to the secondend of the body than the intermediate portion and the upper end portion,an upper region of the bearing race extending between the upper endportion and the intermediate portion and a lower region of the bearingrace extending between the intermediate portion and the lower endportion; the body further including a driven gear having an upper endand an axially spaced apart lower end and comprising a plurality of gearteeth, the plurality of gear teeth of the driven gear extending axiallydownwardly from the first end of the body and extending radially throughthe outer wall of the body, each of the plurality of gear teethincluding an outer surface, the plurality of gear teeth including outersurfaces comprising at least a part of the upper region of the firstarcuate surface; the outer wall of the body further including a firstbearing surface and a second bearing surface for rotatably supportingthe annular rotary knife blade for rotation about the central axis ofrotation, the first bearing surface including an upper bearing face inthe upper region of the first arcuate surface and a lower bearing facein the lower region of the first arcuate surface and the second bearingsurface including an upper bearing face in the upper region of thebearing race and a lower bearing face in the lower region of the bearingrace, the outer surfaces of the plurality of gear teeth comprising atleast a part of the upper bearing face of the first bearing surface; andthe blade section extending from the second end of the body.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the presentdisclosure will become apparent to one skilled in the art to which thepresent disclosure relates upon consideration of the followingdescription of the disclosure with reference to the accompanyingdrawings, wherein like reference numerals, unless otherwise describedrefer to like parts throughout the drawings and in which:

FIG. 1 is a schematic front perspective view of a first exemplaryembodiment of a hand held, power operated rotary knife of the presentdisclosure including a head assembly, a handle assembly and a drivemechanism, the head assembly including a frame body and an assembledcombination of an annular rotary knife blade and an annular split ringblade housing;

FIG. 2 is a schematic exploded front perspective view of the poweroperated rotary knife of FIG. 1;

FIG. 3 is a schematic exploded rear perspective view of the poweroperated rotary knife of FIG. 1;

FIG. 4 schematic top plan view of the power operated rotary knife ofFIG. 1;

FIG. 5 is a schematic bottom plan view of the power operated rotaryknife of FIG. 1;

FIG. 6 is a schematic front elevation view of the power operated rotaryknife of FIG. 1, as seen from a plane indicated by the line 6-6 in FIG.4;

FIG. 7 is a schematic rear elevation view of the power operated rotaryknife of FIG. 1, as seen from a plane indicated by the line 7-7 in FIG.4;

FIG. 8 is a schematic right side elevation view of the power operatedrotary knife of FIG. 1, as viewed from a plane indicated by the line 8-8in FIG. 4;

FIG. 9 is a schematic vertical section view taken along a longitudinalaxis of the handle assembly of the power operated rotary knife of FIG.1, as seen from a plane indicated by the line 9-9 in FIG. 4;

FIG. 10 is a schematic perspective section view along the longitudinalaxis of the handle assembly of the power operated rotary knife of FIG.1, as seen from a plane indicated by the line 9-9 in FIG. 4;

FIG. 11 a schematic vertical section view of the assembled combinationof the annular rotary knife blade and the annular split ring bladehousing of the head assembly of the power operated rotary knife of FIG.1, wherein a load force F1 has been applied to a cutting edge of theannular rotary blade;

FIG. 12 is a schematic vertical section view of the assembledcombination of the annular rotary knife blade and the annular bladehousing of the head assembly of the power operated rotary knife of FIG.1, as seen from a plane indicate by the line 12-12 in FIG. 4, with amounting section of the annular split ring blade housing removed forclarity and wherein a gear force Fg has been applied to a driven gear ofthe annular rotary knife blade by a pinion gear of a gear train of thehead assembly of the power operated rotary knife;

FIG. 12A is a schematic enlarged vertical section view of a portion ofthe assembled combination of the rotary knife blade and the annularblade housing of the head assembly of the power operated rotary knife ofFIG. 1 within a dashed region labeled FIG. 12A in FIG. 12;

FIG. 13 is a schematic top plan view of the annular rotary knife bladeof the head assembly of the power operated rotary knife of FIG. 1;

FIG. 14 is schematic bottom plan view of the annular rotary knife bladeof FIG. 13;

FIG. 15 is a schematic front plan view of the annular rotary knife bladeof FIG. 13;

FIG. 16 is a schematic enlarged section view of a portion of the annularrotary knife blade of FIG. 13, as seen from a plane indicated by theline 16-16 in FIG. 14;

FIG. 17 is a schematic top plan view of the annular split ring bladehousing of the head assembly of the power operated rotary knife of FIG.1;

FIG. 18 is a schematic section view of the annular split ring bladehousing of FIG. 17, as seen from a plane indicated by the line 18-18 inFIG. 17;

FIG. 19 is a schematic front elevation view of a frame body of the headassembly of the power operated rotary knife of FIG. 1;

FIG. 20 is a schematic rear elevation view of a clamp member of the headassembly of the power operated rotary knife of FIG. 1;

FIG. 21 is a schematic front perspective section view of a secondexemplary embodiment of a power operated rotary knife of the presentdisclosure, including a head assembly, a handle assembly and a drivemechanism, the head assembly including a frame body and an assembledcombination of an annular rotary knife blade and an annular split ringblade housing, the section view taken along a longitudinal axis of ahandle assembly;

FIG. 22 is a schematic vertical section view taken along thelongitudinal axis of the handle assembly of the power operated rotaryknife of FIG. 21;

FIG. 23 is a schematic enlarged vertical section view of a portion ofthe assembled combination of the rotary knife blade and the annularblade housing of the head assembly of the power operated rotary knife ofFIG. 21;

FIG. 24 is a schematic vertical section view of the annular split ringblade housing of the head assembly of the power operated rotary knife ofFIG. 21;

FIG. 25 is a schematic enlarged section view of a portion of the annularsplit ring blade housing of FIG. 24;

FIG. 26 is a schematic front perspective section view of a thirdexemplary embodiment of a power operated rotary knife of the presentdisclosure, including a head assembly, a handle assembly and a drivemechanism, the head assembly including a frame body and an assembledcombination of an annular rotary knife blade and an annular split ringblade housing, the section view taken along a longitudinal axis of thehandle assembly;

FIG. 27 is a schematic vertical section view taken along thelongitudinal axis of the handle assembly of the power operated rotaryknife of FIG. 26;

FIG. 28 is a schematic section view of the assembled combination of therotary knife blade and the annular split ring blade housing of the headassembly of the power operated rotary knife of FIG. 26;

FIG. 29 is a schematic enlarged section view of the rotary knife bladeof the head assembly of the power operated rotary knife of FIG. 26;

FIG. 30 is a schematic section view of the annular split ring bladehousing of the head assembly of FIG. 26;

FIG. 30A is a schematic enlarged section view of a portion of theannular split ring blade housing of FIG. 30 within a dashed regionlabeled FIG. 30A in FIG. 30;

FIG. 31 is a schematic front perspective section view of a fourthexemplary embodiment of a power operated rotary knife of the presentdisclosure, including a head assembly, a handle assembly and a drivemechanism, the head assembly including a frame body and an assembledcombination of an annular rotary knife blade and an annular split ringblade housing, the section view taken along a longitudinal axis of thehandle assembly;

FIG. 32 is a schematic vertical section view taken along thelongitudinal axis of the handle assembly of the power operated rotaryknife of FIG. 31;

FIG. 33 is a schematic vertical section view of the assembledcombination of the rotary knife blade and the annular split ring bladehousing of the head assembly of the power operated rotary knife of FIG.31;

FIG. 34 is a schematic enlarged section view of a portion of the rotaryknife blade of the head assembly of the power operated rotary knife ofFIG. 31;

FIG. 35 is a schematic enlarged section view of a portion of the annularsplit ring blade housing of the head assembly of the power operatedrotary knife of FIG. 31;

FIG. 36 is a schematic vertical section view of an alternate exemplaryembodiment of an assembled combination of a rotary knife blade and anannular blade housing suitable for use in, for example, the poweroperated rotary knife of FIG. 21;

FIG. 36A is a schematic enlarged vertical section view of a portion ofthe assembled combination of the rotary knife blade and the annularblade housing of FIG. 36 within a dashed region labeled FIG. 36A in FIG.36;

FIG. 37 is a schematic enlarged vertical section view of a portion of ablade housing support section of the annular blade housing of FIG. 36;

FIG. 38 is a schematic vertical section view of an alternate exemplaryembodiment of an assembled combination of a rotary knife blade and anannular blade housing suitable for use in, for example, the poweroperated rotary knife of FIG. 26;

FIG. 38A is a schematic enlarged vertical section view of a portion ofthe assembled combination of the rotary knife blade and the annularblade housing of FIG. 38 within a dashed region labeled FIG. 38A in FIG.38; and

FIG. 39 is a schematic enlarged vertical section view of a portion ofthe rotary knife blade of FIG. 38.

DETAILED DESCRIPTION First Embodiment—Power Operated Rotary Knife 100

Overview

A hand held, power operated rotary knife of a first exemplary embodimentof the present disclosure is shown generally at 100 in FIGS. 1-10. Thepower operated rotary knife 100 comprises an elongated handle assembly110 and a head assembly or head portion 200, removably coupled to aforward or distal end 112 of the handle assembly 110. As best seen inFIGS. 1-3, the handle assembly 110 includes a generally cylindrical handpiece 120 which is grasped and manipulated by an operator to positionthe head assembly 200 of the power operated rotary knife 100 withrespect to a work product for engaging in cutting and trimmingoperations on the work product. The elongated handle assembly 110extends along a longitudinal axis LA 110 and includes a longitudinallyextending throughbore 115, the longitudinal axis LA extending through acenter of the throughbore 115.

As best seen in FIGS. 1-3, the head assembly 200 of the power operatedrotary knife 100 includes an annular rotary knife blade 300 (FIGS.11-16) supported for rotation about the blade's central axis of rotationR by an annular split ring blade housing 400 (FIGS. 17-18). The rotaryknife blade 300 includes a cutting edge 361 at a lower end 304 of theblade 300. The blade cutting edge 361, when brought into contact with aworkpiece (a product to be cut or trimmed), cuts into the workpiece orproduct, as the operator manipulates the hand piece 120 to move thepower operated rotary knife 100 with respect to the product to perform acutting or trimming operation. The longitudinal axis LA of the handleassembly 110 is orthogonal to and intersects the central axis ofrotation R of the rotary knife blade 300. Motive power to drive therotary knife blade 300 about the central axis of rotation R is providedby a drive mechanism 600 of the power operated rotary knife 100. Theannular blade housing 400 includes a mounting section 402 and a bladesupport section 450 for rotatably supporting the rotary knife blade 300.The annular blade housing 400 comprises a split ring 401 defining anaxially extending central axis or center line CBH of the blade housing400. The blade housing center line CBH is substantially coincident withthe central axis of rotation R of the rotary knife blade 300. That is,both the rotary knife blade 300 and the annular blade housing 400 arecentered about the blade central axis of rotation R. The blade housing400 includes a peripheral split 401 a to allow for expansion of a bladehousing diameter for insertion and removal of the annular rotary knifeblade 300. The mounting section 402 of the blade housing 400 isreleasably secured to a frame body 250 of the head assembly 200 by aclamping assembly 220 to support an assembled combination 500 of theblade housing 400 and the rotary knife blade 300. Specifically, themounting section 402 is sandwiched or affixed between a rearward facingor proximal clamping surface 224 of a rear wall 223 of a clamp body 222of the clamping assembly 220 and a blade housing seating region 252 adefined by an arcuate mounting pedestal 252 of a forward or distalportion 251 of the frame body 250. While the annular rotary knife blade300 and the blade support section 450 of the annular blade housing 400extend circumferentially substantially 360° centered about the centralaxis of rotation R and the blade housing center line CBH, acircumferential cutting region CR (shown schematically in FIG. 4) of thepower operated rotary knife 100 is less than 360°. The cutting region CRrepresents a circumferential extent of assembled combination 500 whereincutting or trimming contact between the blade cutting edge 361 and aproduct or workpiece would properly occur such that a cut or trimmedportion of the product moves smoothly along an inner wall 306 of therotary knife blade 300 through an interior region 309 of the blade 300from a cutting opening CO defined by the blade cutting edge 361 to anexit opening EO at an upper end 302 of the blade 300. Thecircumferential extent of the cutting region CR depends among otherthings on a circumferential extent of the clamp body 222 and theconfiguration of the blade housing mounting section 402. In theassembled combination 500, the circumferential extent of the cuttingregion CR is somewhat greater than 180° of the total 360° circumference.

The frame body 250 (FIGS. 19-20) extends between a distal end 256,defined by a forward wall 251 a of the forward portion 251, and aproximal end 257, defined by a rearward portion 280 of the frame body250. The forward portion 251 of the frame body 250 includes a centralcylindrical region 254 and a pair of arcuate arms 260, 262 extendinglaterally from opposite sides of the central cylindrical region 254. Theframe body 250 also includes the rearward portion 280 extending in arearward direction RW from a proximal end 255 of the central cylindricalregion 254. The rearward portion 280 of the frame body 250 comprises anannular boss 282 which provides a coupling structure for coupling theframe body 250 and, therefore, the head assembly 200, to the handleassembly 110 and additionally provides a support structure for alubrication assembly 240 of the head assembly 200 which provides asource of lubrication that is routed to the driven gear interface region510 and the blade—blade housing bearing interface region 520.

As best seen in FIGS. 11-16, the annular rotary knife blade 300 includesa body 310 and a blade section 360 extending from a lower end or secondend 314 of the body 310. The body

310 of the rotary knife blade 300 includes a driven gear 340 comprisinga plurality of gear teeth or a set of gear teeth 341 that extendradially between and through an inner wall 316 and an outer wall 318 ofthe body 310 adjacent an upper or first end 312 of the body 310. Thedriven gear 340 defines a driven gear region 340 a of the body 310 ofthe rotary knife blade 300. In one exemplary embodiment, the driven gear340 is a ring gear and specifically a face gear. An axial extent of thedriven gear 340 along the outer wall 318 of the body 310 comprises anouter surface 340 b of the driven gear 340 and the driven gear region340 a. The driven gear 340 of the rotary knife blade 300 is engaged by agear train 604 of the drive mechanism 600 of the power operated rotaryknife 100 to rotate the rotary knife blade 300 about its central axis ofrotation R. In one exemplary embodiment, the driven gear 340, that is, aring gear, is rotatably driven by a mating pinion gear 610 of the geartrain 604 of the drive mechanism to form a face gear driveconfiguration.

The outer wall 318 of the body 310 of the rotary knife blade 300includes an arcuate surface 319 that extends from the upper or first end312 of the body and is convex with respect to the blade central axis ofrotation R. By convex, it is meant that the convex arcuate surface 319bows radially outwardly with respect to the blade central axis ofrotation R and bows outwardly from an extent of, for example, the middleand lower portions 318 b, 318 c of the outer wall 318 of the body 310.The arcuate surface 319, when viewed in two dimensions, is characterizedby a constant radius of curvature RAD. That is, as is depictedschematically in FIG. 12A, the arcuate surface 319, when viewed in twodimensions, is characterized by a radius line RD extending from a centerof curvature or center point CPT to the arcuate surface 319, whichdefines the constant radius of curvature RAD of the arcuate surface 319.When the arcuate surface 319 is viewed in three dimensions, asschematically depicted in FIGS. 15 and 16, the arcuate surface 319 ofthe outer wall 318 of the body 310 may be considered as forming aportion of an outer surface of an imaginary ring 319 f. Specifically,the imaginary ring 319 f is annular and, when viewed in radial section,includes a circular cross section 319 g (i.e., the annular ring 319 fhas the configuration of a bull's nose ring). As can be seen in FIG. 15,the ring 319 f has a maximum radius RR (maximum ring radius) defined bya radial distance from the blade central axis of rotation R to a radialoutermost location or vertex or midpoint location 319 k of a secondintermediate portion 319 d of the arcuate surface 319. The midpointlocation 319 k defines a radially outermost extent of the arcuatesurface 319 and, in one exemplary embodiment of the rotary knife blade300, a radially outermost extent of the outer wall 318 of the rotaryknife blade body 310.

With respect to the circular cross section 319 g of the ring 319 f, thecircular cross section 319 g is characterized by the radius RD (FIGS.12A and 16), which is equal to a distance between the center ofcurvature or center point CPT of the arcuate surface 319 and the secondintermediate location or midpoint 319 k of the arcuate surface 319. Withrespect to the circular cross section 319 g of the imaginary ring 319 f,the center point is CPT and the radius of curvature is RAD, since thecircular cross section 319 g of the ring 319 f conforms and iscoincident with the arcuate surface 319. Additionally, the rotationalplane RP, when viewed in two dimensions, may be viewed as a horizontallyextending radius line or straight line RPL (FIGS. 11 and 12A) thatextends orthogonally from the blade central axis of rotation R andpasses through the center point CPT of the arcuate surface 319 and alsopasses through midpoint location 319 k of the intermediate portion 319 dof the arcuate portion 319. In one exemplary embodiment, the arcuatesurface 319 defines substantially a 180° extent of the circular crosssection 319 g extending from an upper end 319 h of the circular crosssection 319 g to a lower end 319 i of the circular cross section 319 g.Advantageously, the arcuate surface 319 of the body outer wall 318includes an entirety of the outer surface 340 b of the driven gear 340and also defines an entirety of an annular bearing surface 322 of therotary knife blade 300. That is, the outer surface 340 b of the drivengear 340 and the annular bearing surface 322 define overlapping portionsof the arcuate surface 319 of the outer wall 318 of the body 310 of therotary knife blade 300. Viewed another way, the arcuate surface 319,when viewed in three dimensions, may be viewed as a protruding bearingbead 311, defining a radially outwardly protruding portion of the outerwall 318 of the blade body 310. The bearing bead 311 comprises orincludes both the outer surface 340 b of the driven gear 340 and theannular, arcuate bearing surface 322 of the rotary knife blade 300. Thebearing surface 322 of the bearing bead 311 is arcuate when viewed invertical section (e.g., FIGS. 11, 12, 12A and 16) in two dimensions and,when viewed in three dimensions, extends around the entirety of the 360°of the circumference CB of the rotary knife blade 300 and therefore isannular. Hence the bearing surface 322 is both annular and arcuate. The360° circumference CB of the annular blade 300 is best seen in FIGS. 13and 14 and is schematically depicted as the dashed line labeled CB inFIG. 14 shown as encompassing the entirety of the 360° of the bladecircumference CB, even though the dashed line CB is depicted as beingradially spaced outwardly from the peripheral edge PE of the blade 360for clarity purposes.

The body 310 of the rotary knife blade 300 also includes an annularbearing region 320 of the rotary knife blade 300 which engages acorresponding annular bearing region 460 of a blade support section 450of the blade housing 400. The rotary knife blade 300 is held in positionwith respect to the blade housing 400 and is supported for rotation withrespect to the blade housing 400 by a blade—blade housing bearingstructure 550 (FIGS. 12 and 12A). The blade—blade housing bearingstructure 550 includes the rotary knife blade annular bearing region320, comprising a rotary knife blade bearing surface 322, which is partof the outer wall 318 of the body 310 and extends radially outwardlywith respect to the blade central axis of rotation R, and the matingannular radially inwardly extending bearing region 460 of the bladehousing 400, comprising a blade housing bearing surface 482, whichconstitutes and is part of an inner wall 452 of the blade supportsection 450 of the blade housing 400.

The annular bearing region 320 of the rotary knife blade 300 comprisesthe annular bearing surface 322, which extends along a portion of theouter wall 318 of the blade body 310. When viewed in axial section, thebearing surface 322 is arcuate. The outer wall 318 of the body 310 ofthe rotary knife blade 300 includes an arcuate surface 319 which isconvex with respect to the blade central axis of rotation R and definesthe radius of curvature RAD and the center of curvature or center pointCPT. The arcuate surface 319 of the outer wall 318 includes a firstupper region 319 a and a second lower region 319 b. The first upperregion 319 a of the arcuate surface 319 of the outer wall 318 of theblade body 310 extends from a first upper end portion 319 c, through thesecond intermediate portion 319 d and terminates at a third lower endportion 319 c. The second intermediate portion 319 d includes a radialoutermost location or midpoint location 319 k of the arcuate surface 319which corresponds to a radially outermost extent of the rotary knifeblade body 310 and a radially outermost extent of the arcuate portion319. The arcuate bearing surface 322 of the rotary knife blade 300includes an upper arcuate bearing surface or face 324 a in the upperregion 319 a of the arcuate surface 319 and a lower arcuate bearingsurface or face 324 b in the lower region 319 b of the arcuate surface319. The upper arcuate bearing face 324 a is curved, converging in adirection proceeding toward the upper end 302 of the rotary knife blade,while the lower arcuate bearing face 324 b is also curved, converging ina direction proceeding toward the lower end 304 of the rotary knifeblade 300. That is, the upper and lower curved surfaces defined by theupper and lower arcuate bearing faces 324 a, 324 b have arcuate orcurved, as opposed to linear, side walls or surfaces. The upper arcuatebearing face 324 a can be viewed as being within an upper zone 328 a(FIG. 12A), that is, the zone 328 a corresponding to a portion of theouter surface 319 j of the annular ring 319 f axially above the radialoutermost location or midpoint location of arcuate portion 319 k of thesecond intermediate portion 318 d, while the lower arcuate bearing face324 b can be viewed as being within a lower zone 328 b, that is, thezone 328 a corresponding to a portion of the outer surface 319 j of theannular ring 319 f axially below the radial outermost location ormidpoint location of arcuate portion 319 k of the second intermediateportion 318 d. When viewed in two dimensions, as seen in FIG. 16, theupper and lower arcuate bearing faces 324 a, 324 b define upper andlower arcuate bearing lines 326 a, 326 b that have a shared or commonradius of curvature RAD and which would intersect at the radialoutermost location or vertex location or midpoint location 319 k of thesecond intermediate portion 318 d of the arcuate portion 319 a.

Advantageously, the arcuate surface 319 of the outer wall 318 of thebody 310 comprises or defines both: a) the rotary knife blade bearingregion 320, that is, the annular, arcuate rotary knife blade bearingsurface 322; and b) an outer surface 340 b of the driven gear 340. Thatis, the arcuate surface 319 of the outer wall 318 of the rotary knifeblade body 310 comprises both the blade bearing region 320 or and inoverlapping axial extent also comprises the outer surface 340 b of thedriven gear 340 of the annular body 310. Stated another way, the outersurface 340 b of the driven gear 340 comprises at least a part of therotary knife blade bearing surface 322 and, with respect to the upperarcuate bearing surface or upper bearing face 324 a of the rotary knifeblade bearing surface 322, the outer surface 340 b of the driven gear340 comprises an entirety of the upper arcuate bearing face 324 a.

The blade support section 450 of the annular blade housing 400 extendssubstantially 360° around an entirety of a circumference of the bladehousing 400. The blade support section 450 is discontinuous in a regionof the split 401 a. A central axis CA of the blade support section 450of the blade housing 400 is coincident or congruent with the axis ofrotation R of the rotary knife blade 300. The blade support section 450includes the annular bearing region 460 including the annular bearingsurface 462. In one exemplary embodiment of the blade housing 400, thebearing region 460 comprises a bearing race 466 that extends radiallyinto and forms a portion of an inner wall 452 of the blade supportsection 450. A back surface or back wall 469 of the bearing race 466 isgenerally V-shaped and includes a pair of converging axially spacedapart upper and lower wall portions or surfaces 466 a, 466 b thatintersect at an intermediate portion 466 c of the bearing race 466. Theintermediate portion 466 c includes a vertex location or midpointlocation 466 k of the bearing race 466. The midpoint location 466 k, ascan best be seen in FIG. 12A, represents a location of the bearing race466 which is radially furthest from the center line CBH of the bladehousing 400. The converging upper and lower surfaces 466 a, 466 b definethe annular bearing surface 462. Specifically, the annular bearingsurface 462 comprises a pair of axially spaced apart, angled orfrustoconical bearing faces, namely, an upper angled or frustoconicalbearing face 464 a and a lower angled or frustoconical bearing face 464b. The upper wall portion or surface 466 a of the bearing race 466comprises the upper frustoconical bearing face 464 a, while the lowerwall portion or surface 466 b of the bearing race 466 comprises thelower frustoconical bearing face 464 b. The upper and lowerfrustoconical bearing faces 464 a, 464 b comprise frustums of respectiveright angled cones, the upper frustoconical bearing face 464 aconverging in a direction proceeding toward the upper end of the firstupper end 456 of the blade housing blade support section 450, that is,in the upward direction UP, while the lower frustoconical bearing face464 c converging in a direction proceeding toward the lower end 458 ofthe blade housing blade support section 460, that is, in the downwarddirection DW.

As part of the blade—blade housing bearing structure 550, the upperarcuate bearing face 324 a of the bearing surface 322 of the rotaryknife blade 300 slidingly engages and bears against the upper angled orfrustoconical bearing face 464 a of the blade housing bearing surface462, while the lower arcuate bearing face 324 b of the rotary knifeblade bearing surface 322 slidingly engages and bears against the lowerangled or frustoconical bearing face 464 b of the blade housing bearingsurface 462, to rotatably support and position the rotary knife blade300 with respect to the annular blade housing 400 and define arotational plane RP of the blade 300. When viewed in two dimensions, theupper and lower frustoconical bearing faces 464 a, 464 b definesubstantially flat or linear, angled, converging axially spaced apartpairs of bearing lines 465 a, 465 b. That is, the upper frustoconicalbearing face 464 a can be viewed in two dimensions as comprising a pairof angled bearing lines 465 a, disposed at opposite radial sides of therotary knife blade 300, as best seen in FIGS. 11, 12 and 12A, convergingthe upward direction UP. Similarly, the lower frustoconical bearing face464 b can be viewed in two dimensions as comprising a pair of angledbearing lines 465 b at opposite radial sides of the rotary knife blade300, converging in the downward direction DW. The rotational plane RP ofthe rotary knife blade 300, which is defined by the blade—blade housingbearing structure 550, is substantially orthogonal with respect to thecentral axis of rotation R of the blade 300. Stated another way, therotary knife blade 300 is supported for rotation by the annular bladehousing 400 by a sliding or journal bearing interface or bearingstructure 550 between respective bearing surfaces 322, 462 of the rotaryknife blade 300 and the blade support section 450 of the blade housing400 and, more specifically, between the respective upper and lowerbearing faces 324 a, 324 b of the rotary knife blade 300 and the upperand lower bearing faces 464 a, 464 b of the blade support section 450 ofthe blade housing 400.

As best seen in FIGS. 1-3, the drive mechanism 600 of the power operatedrotary knife 100 rotatably drives the rotary knife blade 300 at a highangular speed or RPMs, a typical range of RPMs of a rotary knife bladein the power operated rotary knife 100 may be on the order of 900-1,900RPM. The head assembly 200 extends from the distal end 112 of thelongitudinally extending handle assembly 110 which includes the handpiece 120. As mentioned previously, the hand piece 120 is manipulated byan operator of the power operated rotary knife 100 to position therotary knife blade 300 and, specifically, a cutting edge 361 of theblade section 360 within the cutting region CR for cutting or trimming awork product, such as a trimming a layer of fat from an animal carcass.A drive gear 609, specifically, in the present exemplary embodiment, thepinion gear 610, of the gear train 604 meshes with the driven gear 340of the rotary knife blade 300 to rotate the rotary knife blade 300. Thedriven gear 340 of the body 310 of the rotary knife blade 300 includesthe plurality of gear teeth 341 formed on and axially extending into theupper or first end 312 of the body 310. The drive gear 609, that is, thepinion gear 610 of the gear train 604 includes a gear head 614 with aplurality of gear teeth 615 which engage, mesh with and drive theplurality of gear teeth 341 of the driven gear 340 of the rotary knifeblade 300 to rotate the rotary knife blade 300 about the rotary knifeblade central axis of rotation R. The region of the rotary knife blade300 where the driven gear 340 of the rotary knife blade 300 engages andmeshes with the drive gear 609 of the gear train 604 is referred to asthe driven gear interface region 510.

Regions wherein the bearing race 464 of the blade housing 400 engagesbearing surface 322 of the rotary knife blade 300 to support the rotaryknife blade 300 for rotation about the central axis of rotation R arereferred to as the blade-blade housing bearing interface region 520 andthe mating structures of the rotary knife blade 300 and blade housing400 that provide for support the rotary knife blade 300 for rotationabout the central axis of rotation R are referred to as the blade—bladehousing bearing structure or blade—blade housing bearing interface 550.The blade—blade housing bearing structure 550 includes coacting bearingsurfaces 322, 462 of the body 310 of the rotary knife blade 300 and theblade support section 450 of the blade housing 400. Because the rotaryknife blade 300 and the blade support section 450 of the blade housing400 are both annular, the bearing surface 322 of the body 310 of therotary knife blade 300 is annular or circumferential, comprising aportion of an outer wall 318 of the body 310 and, similarly, a portionof an outer wall 308 of the rotary knife blade 300. In the same way, thebearing surface 462 or bearing race 464 of the blade support section 450of the blade housing 400 is annular or circumferential, comprising aportion of an inner wall 452 of the blade support section 450 and,similarly, a portion of an inner wall 400 a of the blade housing 400,the inner wall 452 of the blade support section 450 being a part of andin overlapping relationship with the inner wall 400 a of the bladehousing 400. As used herein, the terms inner and outer wall areunderstood to be taken as measured radially with respect the centralaxis of rotation R of the rotary knife blade 300.

Designers of power operated rotary knives are constantly challenged toimprove the design of such power operated rotary knives with respect tomultiple, sometimes conflicting, objectives. For example, there is adesire for increasing the rotational speed of the rotary knife blade ofa power operated rotary knife. Generally, increasing blade rotationalspeed reduces operator effort required for cutting and trimmingoperations and operators may work longer between sharpenings of therotary knife blade.

There is a desire to reduce heat generated by the power operated rotaryknife during cutting and trimming operations. One source of generatedheat is the blade—blade housing bearing interface region, that is, heatgenerated by the blade—blade housing bearing structure at the bearinginterface between the rotating knife blade and the stationary bladehousing. Reducing generated heat during knife operation will tend toreduce undesirable “cooking” of the product being cut or trimmed. Ifsufficient heat is generated in the bearing region of the rotary knifeblade and blade housing, dislodged pieces or fragments of a productbeing cut or trimmed (e.g., small pieces or fragments of fat, gristle ormeat dislodged during a trimming or cutting operations, such dislodgedpieces or fragments generally referred to as “debris”) in a region ofthe blade—blade housing bearing interface may become so hot that thedebris “cook”. The cooked materials tend to gum up the blade—bladehousing bearing structure and the blade—blade housing bearing interfaceregion resulting in even more undesirable heating. Additionally,reducing generated heat during power operated rotary knife operationwill tend to increase the useful life of various components of a poweroperated rotary knife.

There is also a desire to reduce vibration resulting from the rotationof the rotary knife blade in the blade housing. Rotation of the rotaryknife blade at such high angular speeds may generate excessive,undesirable vibration of the power operated rotary knife if the rotationof the rotary knife blade in the blade housing is not properly balancedand true or if appropriate running or operating clearance between theblade and the blade housing is not provided. If there is vibration ofthe rotary knife blade as it rotates within the blade housing,typically, as rotational speed of the rotary knife blade would beincrease, the vibration of the blade would also increase. Thus,excessive vibration of the rotating rotary knife blade can effectivelylimit the rotational speed of the blade. That is, even if a drivemechanism of a power operated rotary knife could be designed to rotateat a desired fast rotational speed, excessive blade vibration of therotary knife blade within the blade housing, may force the designer tomodify the drive mechanism to limit the rotational speed of blade tomitigate the level of blade vibration.

There is additionally a desire to minimize a cross sectional thicknessof a combination of the blade and blade housing of a power operatedrotary knife to minimize a frictional resistance or “drag” that anoperator will feel during a cutting or trimming operation. The greaterthe “drag” the more effort required on the part of the operator tocomplete the necessary cutting and trimming operations on a workproduct, leading to operator fatigue. Depending on the specific cuttingor trimming application, the size and shape of the rotary knife blademay change e.g., hook style blade vs. straight blade vs. flat blade.Different styles and sizes of rotary knife blades are discussed, forexample, in U.S. Pat. No. 8,726,524 to Whited et al., as previouslymentioned and incorporated by reference herein. Additionally, theconfiguration of the annular blade housing will also change toaccommodate the selected rotary knife blade. However, in all cases,minimizing the cross section of the blade—blade housing combination isan important design objective.

There is also a desire to improve or extend the operational life ofcomponents of the power operated rotary knife including the rotary knifeblade, the blade housing and components of the drive mechanism,including the pinion gear. However, increased blade rotational speed notonly increases heat generated at the blade—blade housing bearinginterface region but also increases a wear rate of the blade—bladehousing bearing structure. The wear rate is a function of bladerotational speed, cutting forces applied to a blade section of therotary knife blade during cutting and trimming operations, and theforces generated by the drive gear (the pinion gear) of the drivemechanism acting on the driven gear (plurality of gear teeth) of therotary knife blade. Increasing the wear rate of the blade—blade housingbearing structure not only reduces the operational life of therespective rotary knife blade and blade housing but also results in aseparation of the respective gear teeth of the drive gear (pinion gear)and the driven gear of the rotary knife blade in the driven gearinterface region leading to undesirable wear of the pinion gear. To anextent, wear at the blade—blade housing bearing interface region resultsfrom loading applied to the blade—blade housing bearing structure bydifferent forces applied to the rotary knife blade including: a) cuttingor load forces, that is, forces applied to the cutting edge 361 of theblade section 360 of the rotary knife blade 300 within the cuttingregion CR as a result of cutting and trimming operations; and b) drivegear forces, that is, forces applied to the driven gear 340 of therotary knife blade body 310 by the meshing of plurality of gear teeth615 of the pinion gear 610 of the drive mechanism with the plurality ofgear teeth 341 of the driven gear 640 of the rotary knife blade 300 torotate the blade 300 about its axis of rotation R.

For simplicity, the load forces are schematically represented by asingle force arrow or vector labeled as F1 in FIG. 11 and will hereafterbe referred to as load force F1, although it is recognized that, inactual operation, the load forces may be applied to variouscircumferential locations of the blade cutting edge 361 and at differingmagnitudes depending on the particular product being cut, an approachangle of the cut or trim (angle between cutting edge of blade and thelayer of product being trimmed resulting from manipulation of the knife100 by the operator), the width of the layer being cut, the depth ofcut, etc. Similarly, for simplicity, the drive gear forces areschematically represented by a single force arrow or vector as Fg inFIG. 12 and will hereafter be referred to as gear force Fg, although itis recognized that the drive gear forces applied to the driven gear 340are more complex than a single force vector. It should also beunderstood, of course, that depending on the particular cutting trimmingapplications of the power operated rotary knife 100, the size andconfiguration of the rotary knife blade 300 and the assembledblade—blade housing combination 500, the specific configurations of thevarious components of the drive mechanism 600, the forces applied to therotary knife blade 300 and/or the reaction forces experienced by therotary knife blade 100 are not limited to the load, gear and reactionforces described herein, but rather include a number of additionalforces, e.g., frictional forces, that are applied to the blade. Further,as the texture and/or density of the product being cut or trimmedchanges, the angle of approach and/or depth of cut changes, thesharpness of the rotary knife blade 300 changes during cutting andtrimming operations, vibration of the blade 300 changes during use, thecombination and magnitude of forces applied to the rotary knife bladealso dynamically change during use of the power operated rotary knife100 and the reaction forces experienced by the rotary knife blade 300from the combination forces similarly change. One of skill in the artwill recognize that the analysis set forth herein is a limited analysisof certain applied forces and reaction forces that impact the wear rateof certain portions of the rotary knife blade 300 and provides anexplanation of certain advantages of the rotary knife blade 100 of thepresent disclosure with respect to those forces and wear rate.

The load force F1 is presumed to act on the cutting edge 361 of therotary knife blade at an angle β (FIG. 11), which is below horizontal ora cutting plane CP defined by the blade cutting edge 361. The exactvalue of the angle β will depend on a number of factors including theapproach angle between the power operated rotary knife 100 and a cuttingsurface of the work product to be cut or trimmed, for example, is theoperator orienting the knife 100 so as to made a thin cut or trim of thework product while moving parallel to the surface of the work product(e.g., trimming a layer of fat from an upper surface of a carcass) ororienting the knife 100 to made a plunge cut deep into the work productto remove or sever a particular portion or part of the work product(e.g., severing a chicken wing from a chicken carcass). The gear forceFg is presumed to act on gear teeth of the rotary knife blade drivengear at an angle α that is determined by a pressure angle of theindividual gear teeth 342 of the set of gear teeth 341 of the drivengear 340 and the angle α is typically 20° with respect to a horizontalcenter plane GCP (FIG. 12) through the set of gear teeth 341 comprisingthe driven gear 340.

Because of the sliding blade—blade housing bearing interface 550 betweenthe rotary knife blade 300 and the blade housing 400 in the assembledcombination 500 of the rotary knife blade 300 and the blade housing 400in the power operated rotary knife 100, as would be recognized by one ofskill in the art, running or operating clearance between the rotaryknife blade 300 and the blade housing 400 must be provided to allow therotary knife blade 300 to rotate relatively freely within the bladesupport section 450 of the annular blade housing 400. Actual runningclearance will depend on a number of factors including the cutting ortrimming application, the amount of time of use and the degree of wearof various components of the power operated rotary knife 100 include therotary knife blade 300 and the blade housing 400, the extent and type oflubrication provided in the blade—blade housing bearing interface region520. However, running clearance typically is on the order of a0.005-0.010 in. radial clearance or gap between the rotary knife blade300 and the blade housing 400. That is, if the bearing surface 322 ofthe rotary knife blade 300 is urged radially against the inner wall 452of the bearing race 466 of the blade support section 450 of the bladehousing 400 such that, in a particular circumferential region orlocation, the upper and lower bearing faces 324 a, 324 b of the bearingsurface 322 of the rotary knife blade 300 are in bearing contact withthe corresponding upper and lower bearing faces 464 a, 464 b of thebearing surface 462 of the blade support section 450 of the bladehousing 400, when viewed at an opposite circumferential location orregion spaced 180° from the bearing contact circumferential location,there would be a 0.005″ to 0.010″ radial gap between the bearing surface322 of the rotary knife blade 300 and the bearing race 466 or bearingsurface 462 of the blade housing 400.

The exact value of the running clearance will be determined by theoperator of the power operated rotary knife 100, however, if the runningclearance is too small, the rotary knife blade 300 will tend to bindduring operation, thus, the operator will understand that the bladehousing diameter will, need to be adjusted to increase the diameter andthus allow the rotary knife blade 300 to run more smoothly in the bladehousing 400. By the same token, if the running clearance is too large,the rotary knife blade 300 will then to wobble around and/or vibrate,thus, the operator will understand blade housing diameter will need tobe adjusted to decrease the diameter and thus allow the rotary knifeblade 300 to run with less vibration/wobble in the blade housing 400.

As one of skill in the art would appreciate, such running or operatingclearance between the rotary knife blade 300 and the blade housing 400allows the rotary knife blade 300 to move slightly within the bearingrace 466 of the blade housing 400. For example, as one circumferentialregion or location of the bearing surface 322 of the rotary knife blade300 is pivoted or moved axially upwardly within the blade housingbearing race 464 during a cutting or trimming operation, thediametrically opposite portion (180° away from the circumferentiallocation or region) of the bearing surface 322 of the rotary knife blade300 (180° away) is generally pivoted or moved axially downwardly withinthe blade housing bearing race 466. In some sense that can be thought ofas the rotary knife blade 300 acting somewhat akin to a teeter-totterwithin the bearing race 466 of the blade housing 400. The pivoting maybe due to load forces F1 applied to the cutting edge 361 of the rotaryknife blade 300 which causes the rotary knife blade 300 to tilt or anglewith respect to the blade housing 400. This is depicted schematically inFIG. 11, wherein the load force F1 is applied to the cutting edge 361 ofthe rotary knife blade 300 at one region of the blade 300 resulting in atilting or teetering of the rotary knife blade 300 with respect to theblade housing 400. This results in a small tilt angle TA between thecentral axis of rotation R of the rotary knife blade 300 and an axiallyextending central axis or center line CBH of the blade housing 400.Obviously, as the load force F1 applied to the cutting edge 361 changesmagnitude and circumferential position, the tilt angle TA will changecircumferential orientation and direction and will vary from a zerovalue (perfect alignment or coincidence between the knife blade axis ofrotation R and the blade housing central axis CBH) to some maximum tiltangle value. Because the clearance between the rotary knife blade 300and the blade housing 400 is on the order of 0.005-0.010 in., it shouldbe understood that the tilt angle TA is very small and the depiction ofFIG. 11 is only a schematic representation of the tilt angle TA.

Accordingly, the specific portions of the mating bearing surfaces 324 a,324 b, 464 a, 464 b of the blade—blade housing bearing structure 550 incontact at any specific location of the rotary knife blade bearingsurface 322 or at any specific location of the coacting blade housingbearing surface 462 will change and, at any given time, will bedetermined, at least in part, by the forces applied to the rotary knifeblade 300 during use of the power operated rotary knife 100. Thus, forany specific portion or region of the respective bearing surfaces of theblade—blade housing bearing structure 550, there may be periods ofnon-contact or intermittent contact with a mating bearing surface orbearing face depending on the loading forces applied to the rotary knifeblade 300 during cutting and trimming operations. The respective bearingfaces 324 a, 324 b, 464 a, 464 b of the rotary knife blade bearingsurface 322 and blade housing bearing surface 462 include surfaces orregions where bearing contact or bearing engagement between the rotaryknife blade 300 and the blade housing 400 can occur during normaloperation of the power operated rotary knife 100, even though it isrecognized that, at any particular point in time during use or operationof the power operated rotary knife 100, because of the operatingclearance between the rotary knife blade 300 and the blade housing 400and the teeter-totter effect, specific portions of the bearing faces 324a, 324 b of the rotary knife blade 300 and specific portions of thebearing faces 464 a, 464 b of the blade housing 400 may not be inbearing engagement or bearing contact or may be in intermittent contactwith mating bearing surfaces. That is, the upper and lower bearing faces324 a, 324 b of the rotary knife blade 300 and the upper and lowerbearing faces 464 a, 464 b of the blade support section 450 of the bladehousing 400 can be viewed as establishing an extent of the bearingcontact between the rotary knife blade 300 and the blade housing 400even though, at a particular time during operation of the power operatedrotary knife 100, specific portions of one or more of the bearing faces324 a, 324 b, 464 a, 464 b may not be in bearing contact or engagementor may be in intermittent contact with mating bearing surfaces. Movementof the rotary knife blade 300 with respect to the blade housing 400 islimited in the axial and radial directions by bearing engagement of theupper and lower bearing faces 324 a, 324 b with the coacting upper andlower bearing faces 464 a, 464 b of the blade housing bearing surface462 of the blade housing 400, the specific geometry of the respectivebearing faces 324 a, 324 b, 464 a, 464 b, and the radial operatingclearance between the rotary knife blade 300 and the blade housing 400.As one of skill in the art would recognize, the need for operating orrunning clearance and the resulting teeter-totter effect, as describedabove, are applicable to all rotary knife blade—blade housingcombinations/embodiments disclosed herein.

As a result of the load force F1 applied to the blade section 360 of therotary knife blade 300 by virtue of the rotary knife blade 300 cuttingthrough a work product (e.g., an animal carcass being cut or trimmed)during cutting and trimming operations with the power operated rotaryknife 100 together with the running or operating clearance between therotary knife blade 300 and the blade housing 400 results in relativemovement of the rotary knife blade 300 within the blade housing 400, asdescribed above. Additionally, as the rotary knife blade 300 tiltswithin the bearing race 466 of the blade housing 400, as schematicallydepicted in FIG. 11, the bearing surface 322 of the rotary knife blade300 is urged against the bearing surface 462 of the blade housing bladesupport section 450. Specifically, the upper bearing face 324 a of theblade bearing surface 322 bears against the upper bearing face 464 a ofthe blade housing bearing surface 462 and the lower bearing face 324 bof the blade bearing surface 322 bears against the lower bearing face464 of the blade housing bearing surface 462. The bearing contact of thecorresponding bearing surfaces 322, 462 due to the load force F1 resultsin load reaction forces Fn1, Fn2 (FIG. 11) being applied to the bladebearing surface 322 by the corresponding blade housing bearing surface462. The direction of the load reaction forces Fn1, Fn2 applied to theupper and lower bearing surfaces 324 a, 324 b of the knife blade 300 arenormal or orthogonal to the specific regions of contact between theupper and lower bearing surfaces 324 a, 324 b of the knife blade 300 andthe respective upper and lower bearing faces 464 a, 464 b of the bladehousing 400.

Also as previously discussed, the plurality of gear teeth 625 of thegear head 614 of the pinion gear 610 engage and rotatably drive themating plurality of gear teeth 341 of the driven gear 340 of the rotaryknife blade 300 to rotate the blade 300 about its axis of rotation R.This engagement and meshing of the pinion gear 610 with the blade drivengear 340 necessarily results in the gear force Fg being applied at theacute angle α with respect to the horizontal gear central plane GCP to adrive or meshing surface 342 b of the individual gear teeth 342 of theset of gear teeth 341 of the driven gear 340, as schematically depictedin FIGS. 12 and 12A. The gear force Fg and the movement of the rotaryknife blade 300 within the blade housing bearing race 466 results ingear reaction forces Fn3, Fn4 being applied to the blade bearing surface322 by the corresponding blade housing bearing surface 462.Specifically, the upper and lower bearing surfaces 324 a, 324 b of theknife blade 300 are subject to gear reaction forces Fn3, Fn4 applied tothe bearing faces 324 a, 324 b by the coacting respective upper andlower bearing faces 464 a, 464 b of the bearing surface 462 of the bladesupport section 450 of the blade housing 400. The gear force Fg urgesthe blade bearing surface 322 of the rotary knife blade 300 against thebearing race 466 of the blade housing, resulting bearing contact betweenthe blade bearing surface 322 and the blade housing bearing surface 462at specific locations of the rotary knife blade 300 and the bladehousing 400, as schematic depicted in FIG. 12. The direction of the gearreaction forces Fn3, Fn4 applied to the upper and lower bearing surfaces324 a, 324 b of the knife blade 300 are normal or orthogonal to thespecific regions of contact between the upper and lower bearing surfaces324 a, 324 b of the knife blade 300 and the respective upper and lowerbearing faces 464 a, 464 b of the blade housing 400.

In prior power operated rotary knives, such as, for example, the poweroperated knives disclosed in U.S. Pat. No. 6,769,184 to Whited, thedriven gear of the rotary knife blade was axially spaced from a bearingregion of the rotary knife blade wherein the bearing surface includedaxially spaced apart bearing surfaces or bearing faces. While thebearing structures of the rotary knife blades and corresponding bladehousings disclosed in the power operated rotary knives of the '184patent advantageously limited movement of the rotary knife blade in boththe axial and radial directions and provided a relatively small areas ofcontact between the mating bearing surfaces of the rotary knife bladeand the blade housing to reduce blade heating in the blade—blade housingbearing interface region. However, due to designers of power operatedrotary knifes continuing desire to increase the rotational speed of therotary knife blade, wear rates of the rotary knife blade, the bladehousing and the drive gear (e.g., pinion gear) of the drive train, amongother components, remains a continuing challenge. As noted above,increasing the rotational speed of a rotary knife blade in a poweroperated rotary knife generally has the undesirable result of increasingthe rate at wear and, therefore, reducing the operational or expectedlife of various components such as the rotary knife blade, blade housingand drive gear, among others, as the wear rates of these components arerelated. For example, a high wear rate of the rotary knife blade in thedriven gear region may cause an undesirable separation between themeshing gear teeth of the drive gear (e.g., the pinion gear) of the geartrain and the gear teeth of the driven gear of the rotary knife blade.This separation of gear teeth in the driven gear interface region maylead to premature wear or a high rate of wear of the gear teeth of thedrive gear (pinion gear) of the gear train and the gear teeth of thedriven gear of the rotary knife blade with a result of reducedoperational life of the driven gear and a reduced operational life ofthe rotary knife blade due to driven gear wear. Similarly, a high wearrate of the rotary knife blade in the blade bearing region, i.e., theregion of the rotary knife blade corresponding to the blade—bladehousing bearing interface region, may not only cause a high wear rateand a reduced operational life of the rotary knife blade because ofpremature wear of the rotary knife blade in the rotary knife bladebearing region but may corresponding cause a higher wear rate in theblade housing bearing region and a resulting reduced operational life ofthe blade housing.

Wear rates of a rotary knife blade of a power operated rotary knife maybe analyzed, at least in part, by examining the reaction forces that thebearing region of a rotary knife blade is subject to during operation ofthe power operated rotary knife. All other things being similar, areduction in the reaction forces applied to the bearing region of arotary knife blade, the lower the wear rate experienced by the rotaryknife blade, both in the rotary knife bearing region and in the rotaryknife driven gear region. Thus, a rotary knife blade design that, undercertain operating conditions, including blade and gear loadingparameters, of the power operated rotary knife 100 (e.g., bladerotational speed, specific blade and blade housing configurations, drivemechanism utilized, characteristics of product being cut, angle ofapproach, depth of cut, etc.), a reduction in reaction forces applied tothe blade bearing region will advantageously result in a reduction in awear rate of the blade bearing region and, potentially, a wear rate inthe blade driven gear region. Such a reduction in wear rate of thebearing region of the rotary knife blade advantageously tends to providea longer operational life for the rotary knife blade, as well longerworking intervals between operator adjustments to the blade housingdiameter to account for wear of the blade bearing region. Equallyadvantageously, if the wear rate for the rotary knife blade is below adesired or target wear rate, blade rotational speed may be increased bythe designer until the wear rate approaches the target wear rate. Thisincrease in blade rotational speed provides for the advantages ofreduced operator effort for cutting and trimming operations and longertime between blade sharpenings, as discussed above.

Generally, as noted above, when a power operated rotary knife is inoperation, the bearing region 320 of the rotary knife blade 300 issubject to gear reaction forces Fn3, Fn4 resulting from the gear forceFg applied by the rotating pinion gear 610 to the driven gear 340 of therotary knife blade 300. In the rotary knife blade 300 of the presentdisclosure, as noted above, advantageously, the arcuate surface 319 ofthe outer wall 318 of the body 310 comprises or defines both: a) therotary knife blade bearing region 320, that is, the annular, arcuaterotary knife blade bearing surface 322; and b) an outer surface 340 b ofthe driven gear 340. That is, the arcuate surface 319 of the outer wall318 of the rotary knife blade body 310 comprises both the blade bearingregion 320 and in overlapping axial and radial extent also comprises theouter surface 340 b of the driven gear 340 in the driven gear region 340a of the body 310. That is, over at least an overlap portion or regionOP (FIG. 12A) of the arcuate surface 319, the outer surface 340 b of thedriven gear 340 and the bearing surface 322 are overlapping orcoincident, that is, the outer surface 340 b of the driven gear 340 andthe bearing surface 322 share the same surface, namely, the arcuatesurface 319 of the outer wall 318 of the blade body 310. Given an axialheight or depth of the plurality of gear teeth 342 of the driven gear340 extending downwardly from the upper end 312 of the blade body 310,in one exemplary embodiment, in the overlap region OP of the arcuatesurface 319, the outer surface 340 b of the driven gear 340 includes oris coincident with or overlaps an entirety of the upper bearing face 324a of the bearing surface 322 and a part or portion of the lower bearingface 324 b of the bearing surface 322. It should be understood, ofcourse that a axial height or depth of the plurality of gear teeth 342may be more or less (deeper or shallower) than the axial height of theplurality of gear teeth 342 depicted schematically in FIG. 12A. An axialheight of the plurality of gear teeth 342 may change depending on thespecific configuration of the rotary knife blade 300, the gear train 604of the drive mechanism 600 and/or the anticipated application of thepower operated rotary knife 100. Thus, for example, if an axial heightof the plurality of gear teeth 342 is shallower, being fully above theintermediate portion 319 d of the arcuate surface 319, the overlapregion OP of the arcuate surface 319 may include only a part of theupper bearing face 324 a and may not even extend into any part of thelower bearing face 324 b. Accordingly, the outer surface 340 b of thedriven gear 340 and the bearing surface 322 includes or is coincidentwith or overlaps only a part or portion of the upper bearing face 324 aand none of the lower bearing face 324 b. Further, the upper and lowerbearing faces 324 a, 324 b of the bearing surface 322 are disposed onthe arcuate surface 319 of the outer wall 318 of the blade body 310 andflank the radial outermost location or midpoint location 319 k of thesecond intermediate portion 319 d of the arcuate surface 319.Accordingly, the upper and lower bearing faces 324 a, 324 b are radiallyspaced from the blade central axis of rotation R at close to maximumradial distance of the outer wall 318 of the body 310 from the centralaxis R of the rotary knife blade 300.

Depending on the specific geometry, including distances (axial andradial) and angular directions, of the upper and lower bearing surfaces464 a, 464 b of the blade support section 450 of the blade housing 400,the gear reaction forces Fn3, Fn4 experienced by the upper and lowerbearing faces 324 a, 324 b of the bearing surface 322 of the rotaryknife blade 300 will vary. However, when viewed axially with respect toor along the blade central axis of rotation R, it is clear that theaxial distance between horizontal center plane GCP of the driven gear340 (where the gear force Fg is applied to the driven gear 340) and therespective upper and lower bearing faces 324 a, 324 b of the bearingsurface 322 and the driven gear 340 of the rotary knife blade body 310are advantageously very small, resulting in a smaller torque or momentof force being experienced by the rotary knife blade 300 as a result ofthe gear force Fg. Indeed, the horizontal center plane GCP of the drivengear 340 passes radially through the upper bearing face 324 a. Statedanother way, as can be seen in FIG. 12, an axial distance Y3 between thelocation where the gear force (represented by gear force vector Fg) isapplied to the driven gear 340 (that is, at a location along thehorizontal center plane GCP of the driven gear 340) is very small withrespect to a location of the reaction force vector Fn3 applied to theupper bearing face 324 a. Similarly, an axial distance Y4 between thelocation where the gear force vector Fg is applied to the driven gear340 is very small with respect to the location of the reaction forcevector Fn4 applied to the lower bearing face 324 b. These small axialdistances Y3, Y4 advantageously result in lower reaction forces Fn3,Fn4, as compared to a situation where the distance between thehorizontal center plane GCP of the driven gear 340 and the upper andlower bearing faces 324 a, 324 b was greater. This close axial proximityof the gear force Fg and the reaction forces Fn3, Fn4 advantageouslyresults in a lower magnitude torque or moment of force being experiencedby the rotary knife blade 300 and results in lower magnitudes for thereaction forces Fn3, Fn4. In the rotary knife blade 300 of the presentdisclosure, the axial distance between the rotary knife bearing region320 and the driven gear 340 is minimized.

Analysis of the rotary knife blade bearing surface reaction forcesindicates that reducing axial distances between the upper and lowerbearing faces 324 a, 324 b and the horizontal center plane GCP of thedriven gear 340 tends to reduce gear reaction forces Fn3, Fn4experienced by the blade upper and lower bearing faces 324 a, 324 bresulting from pinion gear forces Fg. Accordingly, under certainoperating conditions, including blade and gear loading parameters, therotary knife blade 300 of the present disclosure advantageously tends toreduce reaction forces Fn3, Fn4 experienced by the blade upper and lowerbearing faces 324 a, 324 b resulting from gear forces Fg thereby tendingto reduce wear rate of the rotary knife blade 300, specifically, thewear rate of the bearing region 320, that is, the bearing surface 322and the upper and lower bearing faces 324 a, 324 b, and, potentially, awear rate in the blade driven gear region 340 a of the rotary knifeblade 300, specifically, the wear rate of the plurality of gear teeth341. Also, potentially, the wear rate of the pinion gear 610 of the geartrain 604 may be reduced. Such a reduction in wear rate of the bearingregion 340 of the rotary knife blade 100 advantageously tends to providea longer operational life for the rotary knife blade 100. Additionally,such a reduction in wear rate of the bearing region 320 of the rotaryknife blade 300 advantageously tends to provide a longer working timeintervals between operator adjustments to a diameter BHD of bladesupport section 450 of the blade housing 400 to account for wear of theblade bearing region 320. As the blade bearing region 320 wears, theblade 300 will become loose as it rotates within the blade supportsection 450 of the blade housing 400. If the blade 300 is too loosewithin the blade support section 450, the operator will experience anincrease in the vibration of the knife power operated rotary knife 100as the operator continues to use the knife 100 for cutting and trimmingoperations. Ultimately, this will require the operator to cease trimmingand cutting operations to make an adjustment of a circumference of theblade housing 400 to reduce the blade housing diameter BHD, that is, totighten the blade housing blade support section 450 about the rotaryknife blade 300. By reducing the wear rate of the blade bearing region320, the working time interval between operator blade housing diameteradjustments may advantageously be increased.

Equally advantageously, if the wear rate for the rotary knife blade 300,including the bearing region 320, is below a desired or target wearrate, assuming all other wear areas of the blade 300 are withinacceptable wear rates, blade rotational speed may be increased by adesigner until the blade wear rate approaches the target wear rate. Suchan increase in blade rotational speed provides for advantages of reducedoperator effort for cutting and trimming operations and longer timebetween blade sharpenings, as discussed above.

Power operated rotary knives are offered in various sizes, dependingupon the application, characteristics including size and density of theproduct being trimmed or cut, etc. Size of a power operated rotary knifemay be measured in terms of an outer diameter of the annular rotaryblade. Typical annular rotary blade may vary in size from, for example,as 1.4 inches to over 7 inches. For a given annular blade rotationalspeed, e.g., 1,500 RPM, it is clear that the linear velocity of an outerwall of the blade increases with increasing blade diameter. Accordingly,power operated rotary knifes having large diameter blades areparticularly prone to the problems discussed above as for a given bladerotational speed, the larger the diameter of a rotary knife blade, thegreater the linear velocity of the blade as measured at the blade—bladehousing bearing interface region 520. As such, problems of wear of theblade and blade housing bearing surfaces are accentuated in poweroperated rotary knives with large blade diameters. As used herein,rotary knife blades with outer diameters of approximately 5 inches orgreater are considered large diameter blades.

The present disclosure relates to a power operated rotary knife thataddresses certain problems associated with conventional power operatedrotary knives and certain objectives of power operated rotary knifedesign, as set forth above. The power operated rotary knife 100 of thepresent disclosure is suited to be used in connection with both largediameter rotary knife blades and small diameter rotary knife blades. Thepower operated rotary knife 100 includes the head assembly 200, thehandle assembly 110 and the drive mechanism 600. The head assembly 200includes the frame body 250 and the assembled combination 500 of theannular rotary knife blade 300 supported for rotation about the centralaxis of rotation R by the annular blade housing 400.

Drive Mechanism 600

The drive mechanism 600 of the power operated rotary knife 100 providesmotive power to rotate the rotary knife blade 300 with respect to theblade housing 400 about the blade central axis of rotation R and mayinclude some components which may be external to the handle and headassemblies 200, 110 of the power operated rotary knife 100. In oneexemplary embodiment of the power operated rotary knife 100, the drivemechanism 600 includes a drive motor 800, which is external to the poweroperated rotary knife 100, and a flexible shaft drive assembly 700. Theshaft drive assembly 700 includes a rotating drive shaft 702 disposedwithin a non-rotating flexible outer casing or outer sheath 712.Proximal portions of the shaft drive assembly 700 are external to thepower operated rotary knife 100, while distal portions of the shaftdrive assembly 700 are secured to and/or are disposed within thethroughbore 115 of the handle assembly 110 of the power operated rotaryknife 100. Specifically, a distal end of the outer sheath 712 of theshaft drive assembly 700 includes a first coupling 710 which extendsinto the handle assembly throughbore 115 and is releasably secured tothe handle assembly 110 by a drive shaft latching assembly 175 of thehandle assembly 110. When the shaft drive assembly 700 is secured to thehandle assembly 110 by the drive shaft latching assembly 175, a drivefitting 704 at a distal end of drive shaft 702 operatively engages androtates a drive gear 609 of the drive mechanism 600. The drive gear 609,in one exemplary embodiment, is a pinion gear 610 which is both part ofthe drive mechanism 600 and is also part of a gear train 604 of a drivegear assembly 210 of the head assembly 200 of the power operated rotaryknife 100. The drive gear assembly 210 includes the pinion gear 610 anda sleeve bushing 630 which supports the pinion gear 610 for rotationabout a pinion gear axis of rotation PGR. The drive gear assembly 210also includes the driven gear 340 of the rotary knife blade 300. A gearhead 614 formed at a distal end of the pinion gear 610 engages andmeshes with the driven gear 340 of the rotary knife blade 300. The drivefitting 704 of the drive shaft 702 is coupled to and rotates with anoutput shaft of the drive motor 800. Rotation of the drive fitting 704,in turn, rotates the pinion gear 610 about a pinion gear axis ofrotation PGR which, in turn, rotates the rotary knife blade 300 aboutits axis of rotation R.

In one exemplary embodiment, the flexible shaft drive assembly 700includes the first coupling 710 which extends into and is releasablysecured to the handle assembly 110 by the drive shaft latching assembly175 of the handle assembly 110. The first coupling 710 is affixed to thesheath 712 of the shaft drive assembly 700. Rotating within the outersheath 712 is a flexible drive shaft 702. The external drive motor 800provides the motive power for rotating the knife blade 300 with respectthe blade housing 400 about the axis of rotation R via the flexibleshaft drive assembly 700 which comprises a drive transmission includingthe Inner rotating drive shaft 702 rotating within the stationary,non-rotating outer sheath 712. The drive motor 800 includes a coupling802 which releasably receives a mating motor drive coupling 714 affixedto a proximal end of the outer sheath 712 of the shaft drive assembly700. A driven fitting 716 is affixed to a proximal end of the rotatingdrive shaft 702 and, when the motor drive coupling 714 is engaged withthe coupling 802 of the drive motor 800, the driven fitting 716, and,thus, the rotating drive shaft 702 is rotated by a drive shaft of thedrive motor 800. The external drive motor 800 may be an electric motoror a pneumatic motor.

Alternately, the shaft drive assembly 700 may be eliminated and the geartrain 604 the power operated rotary knife 100 may be directly driven byan air/pneumatic motor or an electric motor disposed in a throughbore158 of an elongated central core 152 of a hand piece retaining assembly150 of the handle assembly 110 or in a throughbore 122 of the hand piece120 of the handle assembly 110, if a different hand piece retainingstructure is used. A suitable air/pneumatic motor sized to fit within ahand piece of a power operated rotary knife is disclosed in U.S. Pat.No. 8,756,819 to Whited, et al., issued Jun. 24, 2015. U.S. Pat. No.8,756,819 is assigned to the assignee of the present invention and isincorporated herein it is entirety by reference.

The drive mechanism 600 further includes components which are part ofthe power operated rotary knife 100 including the gear train 604 and thedriven gear 340 formed on the rotary knife blade 300. As can best beseen in FIG. 2, the gear train 604 is part of the drive gear assembly210 of the head assembly 200 and includes the drive gear 609 and thedriven gear 340 of the rotary knife blade 300. In one exemplaryembodiment, the drive gear 609 comprises the pinion gear 610 and thesleeve bushing 630 supports an input shaft 612 of the pinion gear 610for rotation of the pinion gear 610 about the pinion gear axis ofrotation PGR. The pinion gear axis of rotation PGR is substantiallycoincident with the handle assembly longitudinal axis LA. The inputshaft 612 of the pinion gear 610 is rotatably received in a centralopening 634 of the sleeve bushing 630. The gear head 614 of the piniongear 610 engages the driven gear 340 of the body 310 of the rotary knifeblade 300 to rotate the blade 300 about its central axis of rotation R.The male drive fitting 704 at a distal end of the rotating drive shaft702 of the flexible shaft drive assembly 700 rotates the pinion gear 610of the gear train 604. The male drive fitting 704 and the distal end ofthe rotating drive shaft 702 are supported by the first coupling 710 ofthe shaft drive assembly 700. The male drive fitting 704 of the driveshaft engages a female socket or fitting 622 defined by an inner surface620 of the input shaft 612 at a proximal end of the pinion gear 610. Thegear train 604 of the drive mechanism 600 of the power operated rotaryknife 100 transmits rotational power from the rotating drive shaft 702of the flexible shaft drive assembly 700, through the gear train 604,including the pinion gear 610, to rotate the rotary knife blade 300 withrespect to the blade housing 400. In one exemplary embodiment, the gearhead 614 of the pinion gear 610 comprises a spur gear with 33 gearteeth, a 32 diametral pitch and a 20° pressure angle.

The pinion gear 610 and sleeve bushing 630 are supported within aforward cylindrical cavity 290 a which is part of a throughbore 290 ofthe frame body 250. The throughbore 290 extends longitudinally throughthe frame body 250 from a forward wall 251 a to a proximal end 257 ofthe frame body 250 and is in longitudinal alignment and in fluidcommunication with the throughbore 115 of the handle assembly 110. Acentral cylindrical region 254 of the forward portion 251 of the framebody 250 defines the forward cylindrical cavity 290 a. When the flexibleshaft drive assembly 700 is secured to the handle assembly 110 by thedrive shaft latching assembly 175, the drive fitting 704 at the distalend of the rotating drive shaft 702 of the shaft drive assembly 700engages and operatively rotates the pinion gear 610 of the gear train604 of the drive gear assembly 210, which, in turn, rotatably drives thedriven gear 340 of the rotary knife blade 300.

Handle Assembly 110

As can best be seen in FIGS. 2-4, the handle assembly 110 includes thehand piece 120 that is secured to the head assembly 200 by the handpiece retaining assembly 150 of the handle assembly 110. The handleassembly 110 is elongated and extends along the longitudinal axis LAthat is substantially orthogonal to and intersects the central axis ofrotation R of the rotary knife blade 300. The handle assembly 110includes the throughbore 115 which extends along the handle assemblylongitudinal axis LA. The handle assembly throughbore 115 islongitudinally aligned with and in fluid communication with thethroughbore 290 of the frame body 250. The hand piece 120 includes aninner surface 121 that defines the central throughbore 122, whichextends along the handle assembly longitudinal axis LA. The hand piece120 includes a contoured outer handle or outer gripping surface 124 thatis grasped by an operator to appropriately manipulate the power operatedrotary knife 100 for trimming and cutting operations.

As best seen in FIG. 8, the hand piece retaining assembly 150 includesthe elongated central core 152 which extends through the central opening122 of the hand piece 120. A threaded forward outer surface 162 of theelongated core 152 threads into a threaded proximal portion 286 of aninner surface 284 of the annular boss 282 of the frame body 250 tosecure the hand piece 120 to the frame body 250. The inner surface 284of the annular boss 282 of the frame body 250 defines a rearwardcylindrical, longitudinally extending opening 290 b, which is part ofthe frame body throughbore 290. The hand piece retaining assembly 150also includes the spacer ring 190. When the hand piece 200 is beingsecured to the frame body 250, the spacer ring 190 is positioned on theannular boss 282 of the frame body 250 intermediate a forward or distalend 128 of the hand piece 120 and an annular support 246 of thelubrication assembly 240. The hand piece 120 is secured in position byan enlarged proximal end piece 160. As can best be seen in FIG. 2, theend piece 160 includes an interior treaded distal portion 161 whichthreads onto a threaded exterior proximal portion 156 of the elongatedcentral core 152 of the hand piece retaining assembly 150 therebysecuring the hand piece and the spacer ring 190 between the lubricationassembly annular support 246 and a front wall 160 a of the end piece160. Optionally, if desired by the operator of the power operated rotaryknife 100, the spacer ring 190 may be replaced by a thumb support ring(not shown) which provides a resting surface for the operator's thumbthat is spaced radially outwardly from the hand piece 120.

As noted above, the handle assembly 110 also includes the shaft drivelatching assembly 175 (best seen in FIG. 2) which releasably secures theshaft drive assembly 700 to the handle assembly 100. The shaft drivelatching assembly 175 includes an actuator 177 slidingly supported inthe enlarged end piece 160 of the handle assembly 110. The firstcoupling 710 of the shaft drive assembly is received in the throughbore115 defined by the handle assembly 110 and secured in place by theactuator of the shaft drive latching assembly 175. The drive fitting 704at the distal end of the rotating drive shaft 702 of the shaft driveassembly 700 extends into the aligned throughbore 290 of the frame body250 to engage and rotate the pinion gear 610 of the gear train 604 ofthe drive gear assembly 210.

Frame Body 250

The frame body 250 receives and removably supports both the clamp body222 of the clamping assembly 220 and the blade—blade housing combination500. The clamp assembly 250 also helps locate the drive gear assembly210 of the drive mechanism 600, including the pinion gear 610 and thesleeve bushing 630. In this way, the frame body 250 releasably andoperatively couples the drive gear assembly 210 to the blade—bladehousing combination 500 such that the pinion gear 610 of the gear train604 of the drive gear assembly 210 operatively engages the driven gear340 of the rotary knife blade 300 to rotate the knife blade 300 withrespect to the blade housing 400 about the axis of rotation R.

The frame body 250 includes the forward or distal portion 251 and thegenerally cylindrical annular boss 280 generally aligned with thelongitudinal axis LA and extending in a rearward direction RW toward thehandle assembly 110. The forward portion 251 includes the centralcylindrical region 254 and the pair of outwardly extending arcuate arms260, 262. The forward wall 251 a of the frame body 250 defines thearcuate mounting pedestal 252 that defines the seating region 252 a thatreceives and supports the mounting section 402 of the blade housing 400.The frame body forward wall 251 a comprises a forward wall portion 254 adefined by the central cylindrical region 254 and respective forwardwall portions 260 a, 262 a of the arcuate arms 260, 262. The forwardwall 251 a of the frame body 250 also includes a longitudinally recessedclamp receiving region 270 for receiving a frame contacting surface 225of the rear wall 223 of the clamp body 222. The clamp receiving region270 forms a portion of the forward wall 251 a of the frame body 250 andis recessed in the rearward direction RW, as compared to the seatingregion 252 a of the forward wall 251 a. The clamp receiving region 270is generally rectangular in overall shape. The clamp body 222 is securedto the frame body 250 by a pair of a threaded fasteners 228 of theclamping assembly 220 that extend through respective partially threadedopenings 264, 266 in the arcuate arms 260, 262 of the frame body 250 andthread into a pair of threaded openings 223 a in the rear wall 223 ofthe clamp body 222. Securing the clamp body 222 to the frame body 250via the threaded fasteners 228 couples or sandwiches the assembledcombination 500 of the blade housing 400 and the rotary knife blade 300to the frame body 250 and properly positions the rotary knife blade 300to be rotatably driven about the central axis of rotation R by a geartrain 604 of a drive mechanism 600 of the power operated rotary knife100.

The fasteners 228 include unthreaded shaft portions 228 a and threadedend portions 228 b. The threaded end portions 228 b of the fasteners 228are received in the threaded openings 223 a of the clamp body rear wall223 to secure the clamp body 222 to the frame body 250. When thefasteners 228 are loosened such that the clamp body 222 is released fromthe frame body 250 so that the assembled combination 500 of the bladehousing 400 and the rotary knife blade 300 may be removed from the framebody 250, because the unthreaded shaft portions 228 a are captured inthe respective partially threaded openings 264, 266 of the arcuate arms260, 262 the fasteners 228 will not fall out of the openings 264, 266.In order to change the rotary knife blade 300, because the annular bladehousing 400 includes the split 401 a, only one of the two fasteners 228needs to be loosened, namely the fastener 228 extending through theopening 264 in the arcuate arm 260. When the fastener 228 through thearcuate arm 260 is sufficiently loosened, the blade housing diameter maybe increased by prying against one of two circumferential slots 430formed in an outer wall 406 of the mounting section 402. When the bladehousing diameter is sufficiently increased, the rotary knife blade 300may be removed from the blade housing 400 while the clamp body 222remains affixed to the clamp receiving region 270 of the forward wall251 a of the frame body 250 due to the second of the two fasteners 270remaining in a fastened condition.

The frame body throughbore 258 receives and supports the drive gearassembly 210 of the head assembly 200, which is part of the drivemechanism 600 of the power operated rotary knife 100. Specifically, thedrive gear assembly 210 includes the sleeve bushing 630 which isreceived in the forward cylindrical cavity 290 a of the centralcylindrical region 254 of the forward portion 251 of the frame body 250.In turn, the pin ion gear 610 of the drive gear assembly 210 isrotatably supported by the sleeve bushing 630 such that the pinion gear610, when driven by the drive fitting 704 of the flexible shaft driveassembly 700 rotates about the pinion gear axis of rotation PGR. Thegear head 614 of the pinion gear 610 is operatively connected to therotary knife blade driven gear 340 such that the plurality of gear teeth615 of the gear head 614 of the pinion gear 610 mesh with androtationally drive the mating plurality of gear teeth 341 of the drivengear 340 of the rotary knife blade 300 to rotate the rotary knife blade300 about its central axis of rotation R.

A lower surface the forward portion 251 of the clamp body 250 includes adownwardly projecting, arcuate guard 295 to provide additionalprotection to the operator's hand. Just forward of the arcuate guard 295is a pinion gear cover 297 which is secured to the frame body via a pairof threaded fasteners 298 that pass through the pinion gear cover 297and thread into respective threaded openings in the lower surface of theframe body 250. As can be seen in FIG. 2, the pinion gear cover 297,which is part of the head assembly 200, includes an arcuate recess 297 ain a front wall of the pinion gear cover 297 to provide clearance forthe gear head 614 of the pinion gear 610 when the pinion gear cover 297is affixed to the frame body 250.

Lubrication Assembly 240

In addition to the frame body 250, the drive gear assembly 210 and theassembled combination 550 of the rotary knife blade 300 and the annularblade housing 400, in one exemplary embodiment, the head assembly 200additionally includes a lubrication assembly 240. The lubricationassembly 240 includes the annular support 246 which supports alubrication cup 242 and a lubrication cup 242, The annular support 246is rotatably mounted on the annular boss 282 of the rearward portion 280of the frame body 250 between the spacer ring 190 and a rear wall 255 ofthe forward portion 251 of the frame body 250. The annular boss 282includes a receiving shaft 248. The lubrication cup 242 comprises aflexible bladder 243 filled with a food-safe lubricant and a spout shaft244. The spout shaft 244 is received in the receiving shaft 248 of theannular boss 246. When the bladder 243 of the grease cup 297 isdepressed by an operator of the power operated rotary knife, food-safelubricant is routed from the bladder interior through the spout shaft244 and the receiving shaft 248. The lubricant passes through an opening288 in the annular boss 282 of the frame body 250 and is routed througha radial opening 636 and a longitudinally extending passageway 638formed in the sleeve bushing 630 thereby providing lubrication to thegear train 604, including the driven gear interface region 510. A pairof o-rings provide a seal between an inner surface of the annularsupport and the annular boss 282 of the frame body 250 to confine thelubricant such that it flows through the opening 288 of the annular bossof the frame body 250.

Clamping Assembly 220 and Steeling Assembly 230

The clamping assembly 220 includes the clamp body 222 and the pair offasteners 228 that secure the clamp body 222 to the forward wall 251 aof the forward portion 251 of the frame housing 250 and thereby securethe assembled combination 500 of the rotary knife blade 300 and theblade housing 400 to the seating region 252 a of the arcuate mountingpedestal 252 of the forward wall 251 a of the forward portion 251 of theframe housing 250. In one exemplary embodiment, the clamp body 222 ofthe clamping assembly 220 also supports a steeling assembly 230, whichprovides for steeling or straightening the cutting edge 361 of therotary knife blade 300.

The clamp body 222 includes a base 222 a and an upper domed portion 222b. An arcuate rear wall 223 of the clamp body 222 includes the pair ofthreaded openings 223 a which receive respective threaded ends 228 b ofthe threaded fasteners 228. The pair of threaded openings 223 a aredefined in a pair of rearwardly extending bosses 223 c that extend fromthe rear wall 223 of the clamp body 222. A central portion of the rearwall 223 circumferentially between the pair of bosses 423 c includes arecessed generally circular region 223 b that provides clearance for thegear head 614 of the pinion gear 610 of the gear train 604. Surroundingthe recessed region 223 b is a frame body clamping surface 224 which,when the threaded fasteners 228 are threaded into the openings 223 a,bears against the clamp receiving region 270 of the forward wall 251 aof the frame body 250. The frame body clamping surface 224 includes thearcuate outer surfaces 223 d of the bosses 223 c and a lower ledge 227formed in the rear wall 223. In addition to the frame body clampingsurface 224, the rear wall 223 also includes a blade housing clampingsurface 227 which bears against an inner wall 404 of the mountingsection 402 of the blade housing 400. When the clamp body 222 is securedto the frame body 250 the blade housing clamping surface 227 bearsagainst the inner wall 404 of the blade housing mounting section 402 tosecure the mounting section 402 of the blade housing 400 to the framebody 250 and thereby secure the blade—blade housing combination 500 tothe frame body 250 and the head assembly 200. The blade housing clampingsurface 227 includes a lower ledge 227 a that extends along andprotrudes from a lower end of the base 222 a of the clamp body 222. Ascan best be seen in FIG. 20, a left side of the lower ledge 227 includesa scoring area 227 a. The clamp body lines of scoring 227 a bearsagainst a similar scoring area 432 of an inner wall 404 of the bladehousing mounting section 402 (FIG. 18) to inhibit circumferentialmovement or sliding between the blade housing mounting section 402 onthe left side of the blade housing split 401 a and the rear wall 223 ofthe clamp body 222 until and unless the left fastener of the pair offasteners 228 is loosened by the operator of the power operated rotaryknife 100 for purpose of changing the rotary knife blade 300 orproviding increased operating clearance between the blade—blade housingcombination 500. The general curvature or arcuate shape of the rear wall223 matches the general curvature of the blade housing mounting section402 and the general curvature of the forward wall 321 a of the forwardportion 251 of the frame body 250. The clamp body 222 also includes agenerally arcuate forward wall 226 that faces generally toward thedistal end 101 of the power operated rotary knife 100 and the rotaryknife blade axis of rotation R. A central portion of the arcuate forwardwall 226 of the clamp body 222 includes a steeling projection 229 thatsupports the steeling assembly 230. The steeling projection 229 of theclamp body 222 includes an angled throughbore 229 a (FIG. 8) through theprojection 229 that supports a steeling member shaft 228 that extendsthrough the projection throughbore 229 a. Disposed at a lower end of thesteeling member shaft 228 is a generally dome-shaped steeling member226. The steeling assembly 230 further includes an actuator 232 and apush rod 234 extending from the actuator 232 which engages the steelingmember 226. The push rod 234 is slidably supported by the clamp body 222such that it moves generally parallel to the central axis of rotation Rof the rotary knife blade 300. When the actuator 232 is depressed by anoperator of the power operated rotary knife 100 in the downwarddirection DW, the attached push rod 234 urges the steeling member 226into contact with the cutting edge 361 of the rotary knife blade 300 tosteel or straighten the cutting edge 361. A spring disposed in theprojection throughbore 229 a biases the steeling member 226 away fromcontact with the blade cutting edge 361.

The rotational speed of a specific rotary knife blade 300 mounted in thepower operated rotary knife 100 will depend upon the specificcharacteristics of a drive mechanism 600 of the power operated rotaryknife 100, including the external drive motor 800, the flexible shaftdrive assembly 700, the gear train 604 of the drive gear assembly 210,and a diameter and gearing of the rotary knife blade 300. Further,depending on the cutting or trimming task to be performed, differentsizes and styles of rotary knife blades may be utilized in the poweroperated rotary knife 100 of the present disclosure. For example, rotaryknife blades in various diameters are typically offered ranging in sizefrom around 1.4 inches in diameter to over 7 inches in diameter.Selection of a blade diameter will depend on the task or tasks beingperformed. Large diameter rotary knife blades typically refer to rotaryknife blades having an outer diameter of 5 inches or more, while smalldiameter rotary knife blades typically refer to rotary knife blades havean outer diameter of less than 5 inches. The power operated rotary knife100 of the first exemplary embodiment is suitable and advantageously maybe used in connection with both large and small diameter rotary knifeblades. Additionally, various styles of rotary knife blades may also beutilized in the power operated rotary knife 100, including hook bladestyle rotary knife blades, like the rotary knife blade 300, flat bladestyle rotary knife blades, and straight blade style rotary knife blades,among others.

Specific structural and operational details of the head assembly 200 andthe handle assembly 110 are disclosed in U.S. Pat. No. 8,726,524 toWhited et al., issued May 20, 2014. U.S. Pat. No. 8,726,524 to Whited etal. also discloses different styles of rotary knife blades includingflat blade style, hook blade style and straight blade style blades,which may be utilized in the power operated rotary knife 100 of thepresent disclosure. U.S. Pat. No. 8,726,524 to Whited et al. is assignedto the assignee of the present invention and is incorporated herein inits entirety by reference. Specific details of the drive mechanism 600,including the external drive motor 900 and the flexible shaft drivetransmission 700, are disclosed in U.S. Pat. No. 8,968,107 to Rapp etal., issued March 3, 2015. U.S. Pat. No. 8,968,107 to Rapp et al. isassigned to the assignee of the present invention and is incorporatedherein it is entirety by reference.

As used herein, a front or distal end 101 of the power operated rotaryknife 100 is an end of the knife 100 that includes the blade—bladehousing combination 500, while a rear or proximal end 102 of the poweroperated rotary knife 100 is an end of the knife 100 that includes thehandle assembly 110, and specifically, the enlarged end piece 160threaded onto or attached to the elongated central core 152 of the handpiece retaining assembly 150. Upward or upward direction UP means in adirection generally parallel to the central axis of rotation R of therotary knife blade 300 and, as shown in FIGS. 5 and 6, going in adirection from a first, upper end 456 of the blade support section 450of the blade housing 400 to a second, lower end 458 of the blade supportsection 450. Downward or a downward direction DW means an axialdirection generally parallel to the central axis of rotation R of therotary knife blade 300 and the central axis CBH of the blade housing 400and, as shown in FIGS. 6-8, going in a direction from the second, lowerend 458 of the blade housing blade support section 450 to the first,upper end 456 of the blade support section 450. Annular, as used herein,means generally ring-like or generally ring-shaped in configuration andincludes configuration wherein the ring include or does not include asplit extending through a diameter of the ring or annul us. Axiallyabove or axially spaced above, as used herein, means positioned above asviewed with respect to an axis, for example, the central axis ofrotation R of the rotary knife blade 300, even if the two elements arenot in axial alignment with respect to the axis. For example, thebearing race 322 of the rotary knife blade 300 is axially above oraxially spaced above the cutting edge 361 of the rotary knife blade 300with respect to the blade central axis of rotation R even though theblade bearing race 322 is spaced radially outwardly from the bladecutting edge 361 with respect to the blade central axis of rotation R.The terms axially below or axially spaced below, as used herein, meanspositioned below as viewed with respect to an axis, for example, thecentral axis of rotation R of the rotary knife blade 300, even if thetwo elements are not in axial alignment with respect to the axis. Forexample, the cutting edge 361 of the rotary knife blade 300 is axiallybelow or axially spaced below the bearing race 322 of the rotary knifeblade 300 with respect to the blade central axis of rotation R eventhough the blade cutting edge 361 is spaced radially inwardly from theblade bearing race 322 with respect to the central axis of rotation R.Similarly, axially extending, as used here, means one element extendsfrom and is positioned above or below a second element with respect toan axis, even if the two elements are not in axial alignment withrespect to the axis. For example, the blade section 360 extends axiallyfrom the body 310 with respect to the blade axis of rotation R eventhough portions of the blade section 360 are spaced radially inwardlyfrom the body 310 with respect to the blade central axis of rotation R.Similarly, the terms radially offset from, radially outward of, radiallyinward of, as used herein, means one element is positioned offset from asecond element, as viewed along a radius line extending radially from anaxis, for example, the central axis of rotation R of the rotary knifeblade 300, even if the two elements are not in radial alignment alongthe radius line because one element is axially above or axially belowthe other element.

Rotary Knife Blade 300

In one exemplary embodiment of the present disclosure, the rotary knifeblade 300 of the power operated rotary knife 100 is a one-piece,continuous annular structure and rotates in the blade housing 400 aboutthe central axis of rotation R. As can best be seen in FIGS. 11-16, therotary knife blade 300 includes an upper end or a first end 302, and anaxially spaced apart lower end or a second end 304, the lower or secondend 304 includes the cutting edge 361 of the blade 300. The rotary knifeblade 300 further includes an inner wall 306 and a radially spaced apartouter wall 308. The rotary knife blade 300 is comprised of the upperannular body 310 and an annular blade section 360 extending axially andradially inwardly from the body 310. As can be seen in FIGS. 11-15, thebody 310 and the blade section 360 are both radially centered about thecentral axis of rotation R, that is, the body 310 and the blade section360 are both concentric about the central axis of rotation R. In oneexemplary embodiment, the rotary knife blade 300 is a so-called hookblade style rotary knife blade having the blade section 360 extendingradially inwardly and axially downwardly with respect to the body 310and defining an obtuse cutting angle CA (FIG. 11) and characterized bythe blade section 360 having a generally frustoconical inner wall 366that is suited for trimming or cutting relatively thin layers ofmaterial from an object to be trimmed (e.g., cutting or trimming a thinlayer of fat or meat from an animal carcass). The generally planar innerwall 366 of the blade section 360 comprises a lower pail of the innerwall 306 of the rotary knife blade 300. The inner wall 306 includes agenerally curved path of travel for cut or trimmed material. The hookblade 300 is particularly useful for trimming relatively thin layers ofmaterial from a product, for example, trimming a thin layer of fat ormeat tissue from a relatively planar, large piece of meat, as the poweroperated rotary knife 100 is moved over the product in a sweepingmotion. For trimming thicker layers of material from a product, the hookblade 300 would not be as efficient because the curved path of travel ofthe cut or trimmed material layer would result in the power operatedrotary knife 100 experiencing more drag and resistance during catting ortrimming. Thus, more effort would be required by the operator to moveand manipulate the power operated rotary knife 100 to make the desiredcuts or trims. Other rotary knife blade styles, such as flat blade andstraight blade styles, are suitable for use with the power operatedrotary knife 100 and the present disclosure contemplates differingstyles and sizes of rotary knife blades and associated blade housing forrotational support of such differing blades. An explanation of differingrotary knife blade styles is found in the aforementioned U.S. Pat. No.8,726,524 to Whited et al., which is assigned to the assignee of thepresent invention and is incorporated herein in its entirety byreference. In one exemplary embodiment, the rotary knife blade 300 has amaximum outer diameter ODB of 3.56 in.

The annular body 310 includes the upper or first end 312, whichcorresponds to the upper or first end 302 of the rotary knife blade 300,and an axially space apart lower or second end 314, which defines aboundary between the body 310 and the blade section 360. The upperannular body 310 further includes an inner wall 316, defining a portionof the blade inner wall 306, and, spaced radially outwardly (that is ina radial direction away from the blade axis of rotation R) from theinner wall 316 is the outer wall 318 of the body 310. The outer wall 318of the body 310 defines a portion of the blade outer wall 308. In oneexemplary embodiment, the outer wall 318 of the body 310 comprises threeregions or portions, an upper portion 318 a adjacent the upper or firstend 312 of the body 310, a radially recessed middle portion 318 b, and alower portion 318 c adjacent the lower or second end 314 of the body310. The upper portion 318 a of the outer wall 318 of the blade annularbody 310 advantageously comprises an arcuate surface 319 that bothincludes the bearing surface 322 of the rotary knife blade 300 andincludes an outer surface 340 b of the driven gear 340. The arcuatesurface 319 comprises an outer surface 342 a of each of the individualteeth 342 of the plurality of teeth 341 of the drivers gear 340 of therotary knife blade. Stated another way, the arcuate surface 319, definesboth the outer surface 340 a of the driven gear 340 and defines thebearing region 320, that is, the bearing surface 322 of the rotary knifeblade 300. The outer surface 340 a of the driven gear 340 and thebearing surface 322 of the rotary knife blade 300 are coincident over atleast an overlapping portion OP of the arcuate surface 319. In theoverlapping portion OP of the arcuate surface 319, the outer surface 340a of the driven gear 340 and the bearing surface 322 are coincident,being in both overlapping axial alignment (i.e., as viewed with respectto the rotary knife blade axis of rotation R) and overlapping radialalignment (i.e.. as viewed along a radius line extending orthogonallyfrom the blade axis of rotation R). As discussed above with respect towear rates, the overlapping radial and axial structure or configurationof the driven gear 340 and the bearing surface 322 of the rotary knifeblade 300 of the present disclosure, under certain operating conditionsand parameters, may advantageously reduce the gear reaction forces Fn3,Fn4 resulting from the gear force Fg and may advantageously provide fora reduced wear rate of the bearing region 320 of the rotary knife blade300 and/or reduced wear rate of the driven gear 340 and/or reduced wearrate of the pinion gear 610. Alternatively, if predetermined wear rateor expected life requirements is imposed on a designer of a poweroperated rotary knife for the rotary knife and/or the pinion gear, theaxially overlapping structure of the driven gear 340 and the bearingsurface 322 of the rotary knife blade 300 may enable the designer toadvantageously provide for increased rotational speed of the rotaryknife blade, while still adhering to the predetermined wear rate orexpected life requirements. Moreover, a reduction in wear rate of thebearing region 340 of the rotary knife blade 100 advantageously tends toadditionally provide a longer working time intervals between operatoradjustments to the blade housing diameter BHD of the blade supportsection 450 of the blade housing 400 to account for wear of the bladebearing region 320, as explained previously.

The arcuate surface 319 of the upper portion 318 a of the outer wall 318of the blade annular body 310 extends from a first upper end portion 319c through the second intermediate portion 319 d and terminates at athird lower end portion 319 e. The second intermediate portion 319 dincludes the midpoint location or radial outermost location 319 k of thearcuate portion 319. The radial outermost location 319 k defines theradially outermost extent of the arcuate surface 319 and the radiallyoutermost extent of the rotary blade body 310. The first upper endportion 319 c of the arcuate surface 319 is axially closer to the upperor first end 312 of the body 310 of the rotary knife blade 300 than thesecond intermediate portion 319 d and the third lower end portion 319 eof the arcuate surface 319 is axially closer to the lower or second end314 of the body 310 of the rotary knife blade 300 than the secondintermediate portion 319 d. The second intermediate portion 319 dincludes the midpoint location or radial outermost location 319 k whichrepresents the furthest radial extent of the rotary knife blade 300 andthus defines the blade maximum outer diameter ODB and also defines themaximum radius RR of the annular ring 319 f. The arcuate surface 319 isconvex with respect to the blade central axis of rotation R and, whenviewed in two dimensions in vertical or axial section, that is, whenviewed in two dimensions with respect to or along a vertical or axialplane parallel to the blade central axis of rotation R, defines theradius of curvature RAD and the center of curvature or center point CPTof the arcuate surface 319. As noted previously, fey convex, it is meantthat the convex, arcuate surface 319 bows outwardly with respect to anextent of, for example, the middle and lower portions 318 b, 318 e ofthe outer wall 318 of the body 310 and bows outwardly with respect tothe blade central axis of rotation R. In one exemplary embodiment, theradius of curvature RAD of the convex arcuate surface 319 is 0.047 in.and, accordingly, the center of curvature or center point CPT is 0.047in radially in ward from the maximum outer diameter ODB, as defined bythe second intermediate portion 319 d and, more specifically, by themidpoint location 319 k of the second intermediate portion 319 d. Thearcuate surface 319 includes the upper region 319 a, which extendsbetween the first upper end portion 319 c and the second intermediateportion 319 d, and the lower region 319 b, which extends between thesecond intermediate portion 319 d and the third lower end portion 319 e.The arcuate surface 319 includes or defines the bearing region 320 ofthe rotary knife blade 300. That is the bearing region 320 comprises anarcuate bearing surface 322 which is encompassed within the arcuatesurface 319 of the outer wall 318 of the blade body 310. Specifically,the arcuate bearing surface 322 of the rotary knife blade 300 includesthe upper arcuate bearing surface or face 324 a in the upper region 319a of the arcuate surface 319 and the lower arcuate bearing surface orface 324 b in the lower region 319 b of the arcuate surface 319. Theupper arcuate bearing face 324 a, when viewed in three dimensions, is acurved surface, converging in a direction proceeding toward the upperend 302 of the rotary knife blade, while the lower arcuate bearing face324 b is also a curved surface, converging in a direction proceedingtoward the lower end 304 of the rotary knife blade 300. That is, asmentioned previously, it should be recognized that the upper and lowercurved surfaces defined by the upper and lower arcuate bearing faces 324a, 324 b have arcuate or curved, as opposed to linear, side walls. Thecenter point CPT of the radius of curvature RAD of the arcuate surface319 of the outer wall 318 of the blade body 310 is radially alignedalong a radius line RD (FIG. 11) extending orthogonally from the rotaryknife blade axis of rotation R to the midpoint location or radialoutermost location 319 k of the second intermediate portion 319 d of thearcuate surface 319, that is, the radius line RD extending orthogonallyfrom the central axis of rotation R to the radial outermost location 319k of the arcuate surface 319 extends through or passes through thecenter point or center of curvature CPT of the arcuate surface 319.

Extending axially in the downward direction DW from the upper or firstend 312 of the body 310 is the driven gear 340. In one exemplaryembodiment, an axial extent of each of the plurality of gear teeth 341of the driven gear 340 extends axially below the midpoint location 319 kof the second intermediate portion 319 d. Specifically, a lower end 349b of the driven gear 340 (and, thus, a lower end 341 c of each of dieplurality of gear teeth 341), as viewed along the outer wall 318 of thebody 310, extends to a position 318 d that is between the secondintermediate portion 319 d and the third lower end portion 319 e to aposition 318 d. Thus, advantageously, the outer surface 340 b of thedriven gear 340 defines: 1) an entirety of the upper arcuate bearingface 324 a: and 2) at least a portion of the lower arcuate bearing face324 b. Such an overlapping axial configuration of the bearing surface322 and the outer surface 343 b of the driven gear 340 willadvantageously tend to reduce the blade wear rate, as discussedpreviously.

The middle portion 318 b of the outer wall 318 of the annular body 310extends from an upper end 318 d to a lower end 318 e and defines aradially recessed region 330 of the outer wall 318. The radiallyrecessed region 318 forms an annular channel 331. The annular channel331 is generally rectangular when viewed in cross section (FIGS. 11 and16) and is radially recessed with respect to the axis of rotation R ascompared to a radial extent of the midpoint location or radial outermostlocation 319 k of the second intermediate portion 319 d of the arcuatesurface 319 of the upper portion 318 a of the outer wall 318 and aradial extent of an outer vertical surface 336 of the lower portion 318c of the outer wall 318. The annular channel 331 receives a matingradially projecting annular land 471 of the inner wall 452 of the bladesupport section 450 of the blade housing 400 to form a labyrinth sealthat advantageously inhibits or mitigates the ingress of debris formedin the cutting/trimming process (small pieces of meat, fat, bones,gristle, connective tissue, etc) into the blade—blade housing bearinginterface region 520. The annular channel 331 of the rotary knife bladebody outer wall 318 and the mating annular land 471 of the blade housingblade section inner wall 452 are in close proximity but are not inbearing contact during normal operation of the power operated rotaryknife 100.

The annular channel 331 includes a generally horizontal upper surface332, an angled or frustoconical middle surface 333, and a generallyhorizontal lower surface 334, bridged by two short arcuate transitionsurfaces extending between the horizontal upper surface 332 and thefrustoconical middle surface 333 and between the frustoconical middlesurface 333 and the horizontal lower surface 334. The frustoconicalmiddle surface 333 converges in a direction proceeding to the upper orfirst end 312 of the Made body 310 and because the middle surface 333 isangled, the effective distance that debris must travel from the lowerend 458 of the blade support section 450 of the blade housing 400 tomigrate into the blade—blade housing bearing interface region 520 isincreased thereby increasing the effectiveness of the labyrinth sealformed by the mating configurations of the blade annular channel 331 andthe blade housing annular land 471.

Additionally, the annular channel 331 of the rotary knife blade 300advantageously serves to limit, by a hard stop, axial movement of theblade 300 within the blade housing 400. As noted above, the annularchannel 322 receives the mating annular land 471 of the blade housing400. The blade housing 400 is a split blade housing to allow forexpansion of the blade housing for the purpose of changing rotary knifeblades. As explained above, sufficient operating or running clearance isnecessary so that rotary knife blade 300 rotates relatively freelywithin the blade housing 400 reducing friction and thereby reducing heatgenerated in the blade—blade housing bearing interface region 520.However, if too great of an operating or running clearance is provided,that is, the diameter of the blade housing 400 is too great, forexample, because the operator did not adjust the blade housing diameterappropriately when changing rotary knife blades or for some reasonduring use of the power operated rotary knife 100, the blade housingdiameter increased causing the blade 300 to be excessively loose withinthe blade housing 400, the interfitting of the annular channel 331 andthe annular land 471 functions as a hard stop to prevent excessive axialmovement of the blade 300 within the blade housing 400. That is,excessive movement of the blade 300 with respect to the blade housing400 in an axial upward direction UP would be stopped by contact or ahard stop between the horizontal upper surface 332 of the annularchannel 331 and a horizontal upper surface 472 of the annular land 471.Excessive movement of the blade 300 with respect to the blade housing400 in an axial downward direction DW would be stopped by contactbetween the horizontal lower surface 334 of the annular channel 331 anda horizontal vertical surface 477 of the annular land 471.

The lower portion 318 c of the outer wall 318 of the annular body 310extends from an upper end 318 f to a lower end 318 g. The lower end 318g of the lower portion 318 c is coincident with the lower or second end314 of the annular body 310. The lower portion 318 c includes an angledtransition surface 335 which extends in a radially outwardly directionfrom the horizontal lower surface 334 to an outer vertical surface 336.In one exemplary embodiment, the radial extent of the outer verticalsurface 336 is just less than the radial extent of the midpoint orradial outermost location 319 k of the second intermediate portion 319 dof the arcuate surface 319 of the upper portion 318 a of the outer wall318. Thus, the outer vertical surface 336 does not define the outerdiameter ODB of the rotary knife blade 300.

The inner wall 316 of the annular body 310 extends from an upper end 316a to a lower end 316 b and includes, at the upper end 316 a, a generallyvertical surface 337 that extends axially from the upper or first end312 of the body 310 and defines an inner surface 340 c of the drivengear 340. The inner wall 316 also includes an arcuate surface 338 thatis part of a convex arcuate surface 307 of the inner wall 306 of therotary knife blade 300. The convex arcuate surface 307 includes an uppercurved portion 307 a of the arcuate surface 307 that converges in theupward direction UP toward the upper end 302 of the rotary knife blade300 and a lower curved portion 307 b that converges in the downwarddirection DW toward the lower end 304 of the blade 300. The convexarcuate surface 307 is centered about the blade central axis of rotationR. Extending along most of the axial extent of the rotary knife blade300, the convex arcuate surface 307 provides for smooth movement of cutor trimmed material in an upward direction UP from the cutting openingCO defined by the blade cutting edge 361 to the vertical surface 337 ofthe inner wall 316 of the body. The vertical surface 337 of the innerwall 316 of the body 310 continues the smooth movement of material fromthe convex arcuate surface 307 to the exit opening EO defined by theupper or first end 312 of the blade annular body 310.

In one exemplary embodiment, the blade section 360 of the rotary knifeblade 300 includes an upper end 362, which defines the boundary betweenthe body 310 and the blade section 360, and an axially spaced apartlower end 364. The upper end 362 of the blade section 360 terminateswhere the outer wall 368 has a “knee” or discontinuity point 362 a. Thatis, the linear, angled outer wall 368 of the blade section 360 abruptlytransitions at the “knee” or discontinuity point 362 a to the verticallyextending lower section 318 c of the outer wall 318 of the blade body310. Effective sharpening of the blade cutting edge 361 becomes moredifficult above the “knee” point 362 a due to the discontinuity of theblade outer wall 308 resulting from the “knee” or discontinuity point362 a. The lower end 364 of the blade section 360 includes the cuttingedge 361 of the rotary knife blade 300. The knife blade section 360includes an inner wall 366, defining a portion of the blade inner wall306, and a radially spaced apart outer wall 368, defining a portion ofthe blade outer wall 308. The inner and outer walls 366, 368 aregenerally parallel. The inner wall 366 of the blade section 360 includesan upper arcuate or curved region 366 a which is part, of the convexarcuate surface 30 of the inner wall 306 of the rotary knife blade 300and a lower angled or frustoconical region 366 b adjacent the bladecutting edge 361. The lower frustoconical region 366 b converges in adirection proceeding toward the lower end 304 of the blade 300. Theouter wall 368 of the blade section 360 includes an angled orfrustoconical region 368 a, which like the lower angled or frustoconicalregion 366 b converges in a direction proceeding toward the lower end304 of the blade 300. The angled or frustoconical region 368 a and thelower angled or frustoconical region 366 b of the outer and inner walls368, 366 are substantially parallel are both centered about the bladecentral axis of rotation R. The cutting edge 361 defines the circular orcutting opening CO of the rotary knife blade 300 through which trimmedor cut material passes. Additionally, the cutting edge 361 defines thecutting plane CP of the rotary knife blade 300. The blade cutting planeCP is substantially orthogonal to the blade central axis of rotation R.Cut or trimmed material flows or moves from the cutting edge 361 throughthe cutting opening CO, along the inner wall 306 of the rotary knifeblade 300, that is, along the inner wall 366 of the blade section, thenalong the inner wall 316 of the annular body 310, in a generally upwarddirection UP from the cutting edge 361 to a circular exit opening EOdefined by a vertex 313 between the inner wall 316 of the body 310 andthe upper or first end 312 of the body 310. In one exemplary embodimentof the rotary knife blade 300, the cutting opening CO is approximately3.27 in. The vertex 313 also defines the intersection between the innerwall 306 and the upper end 302 of the rotary knife blade 300. Thecutting edge 361 is formed at the intersection of the inner wall 366 anda short horizontal region 370 bridging the inner and outer walls 366,368 of the blade section 360. The short horizontal region 370 definesboth the lower end 364 of the blade section and the lower end 304 of therotary knife blade 300.

The driven gear 340 includes a plurality or set of circumferentiallyspaced apart gear teeth 341. The driven gear 340 and each of the gearteeth 342 of the plurality of gear teeth 331 extend radially between andextend through the inner and outer walls 316, 318 of the annular body310. The driven gear 340 comprises the driven gear region 341 a whereinthe gear head 614 of the pinion gear 316 engages the gear teeth 341 ofthe driven gear 340 to rotate the rotary knife blade 300 about thecentral axis of rotation R. The driven gear 340 extends axially from anupper end 349 a to the lower end 349 b. As can best be seen in FIG. 16,the individual teeth 342 of set of gear teeth 341 of the driven gear 340extend vertically upwardly as generally angled pie slice shaped orv-shaped teeth 342 from an annular base lower surface 343 defined by abottom land 344 between adjacent gear teeth 342 to an annular top orupper surface 345 defined by the respective top lands 346 of the set ofgear teeth 341. The upper surfaces 345 or top lands 346 of the set ofgear teeth 341 define the upper end 349 a of the driven gear 340, theupper end 302 of the rotary knife blade 300 and the upper or first end312 of the annular body 310, while the lower surface 343 and bottom land344 of the set of gear teeth 341 define the lower end 349 b of thedriven gear 340. Disposed between each pair of adjacent gear teeth 342of the plurality of gear teeth 341 is a generally v-shaped or pie shapedopening or gap region 348. The v-shaped gap regions 348, taken together,form a set of v-shaped gaps 348 a that extend circumferentially aboutthe upper end 312 of the annular body 310 and within the driven gearregion 340 a, extending downwardly from the upper end 349 a of thedriven gear 340 to the lower end 349 b of the driven gear 340 andextending radially between and through the inner and outer walls 316,318 of the annular body 310. Because the set of v-shaped gaps 348 aextend through the body outer wall 318, the arcuate surface 319 of theouter wall 318 is interrupted by peripheral or circumferential v-shapedopenings 348 b in the outer wall 318. Thus, in the overlap region OP,the bearing surface 322 is circumferentially interrupted by the set ofv-shaped openings 348 b in the outer wall 318 in the overlap region OP.

In one exemplary embodiment, given an axial height of the plurality ofgear teeth 341 of the driven gear 340 extending downwardly from theupper end 312 of the blade body 310, an entirety of the upper bearingface 324 a is circumferentially interrupted by the set of v-shapedopenings 348 b and a part or portion of the lower bearing face 324 b isinterrupted by the set of v-shaped openings 348 b. However, it should berecognized that if an axial height of the plurality of gear teeth 342 isless or shallower, it may be the case that only a part of the upperbearing face 324 a is circumferentially interrupted by the set ofv-shaped openings 348 b and none of the lower bearing face 324 b isinterrupted by the set of v-shaped openings 348 b. In one exemplaryembodiment of the rotary knife blade 300, an axial or vertical distancebetween the upper and lower ends 349 a, 349 b of the driven gear 340,that is, a height of the driven gear 340 is approximately 0.074 in. Asnoted previously, the axial height of the driven gear 340 is dependenton a number of factors including the design and position of the geartrain 604, the specific configuration of the rotary knife blade 300and/or the cutting/trimming tasks the power operated rotary knife 100 isintended for.

Viewing the driven gear 341 in a radial direction, the driven gearextends from the vertically extending inner surface 340 c to thearcuately extending outer surface 340 b. A maximum outer diameter of thedriven gear 340, as measured radially with respect to the blade centralaxis of rotation R, is coincident the maximum rotary knife blade outerdiameter ODB. That is, the outer surface 340 b of the driven gear 340extends from the first upper end portion 319 c of the arcuate surface319, through the entirety of the upper region 319 a, through the secondintermediate portion 319 d (including the midpoint location 319 k of thesecond intermediate portion 319 d which defines the blade outer diameterODB) and into the lower region 319 b. In one exemplary embodiment, aradial distance between the inner and outer surfaces 340 c, 340 b of thedriven gear 340 is approximately 0.160 in. The outer surface 340 b ofthe driven gear 340 is defined by a collective total of outer surfaces342 c of respective outer surfaces 342 a of the individual gear teeth342 of the set of gear teeth or plurality of gear teeth 341. Thus, theouter surface 340 b driven gear 340 could equivalently be referred to asand is the same as the outer surfaces 342 c of the plurality of gearteeth or the set of gear teeth 342. Advantageously, the outer surface340 b of the driven gear 340, that is, the outer surfaces 342 c of theset or plurality of gear teeth 341, is arcuate, conforming to andforming a part of the arcuate surface 319 of the outer wall 318 of thebody 310. Specifically, the outer surface 340 b of the driven gear 340,that is, the outer surfaces 342 c of the plurality of gear teeth 342,forms or defines all of the upper region 319 a of the arcuate surface319, forms or defines the second intermediate portion 319 d (whichincludes the midpoint location 319 k defining the blade outer diameterODB) of the arcuate surface 319, and forms or defines a portion of thelower region 319 b of the arcuate surface 319.

In one exemplary embodiment, an overall axial height of the rotary knifeblade 300 is approximately 0.365 in. and the driven gear 340 comprises aspur gear with 110 gear teeth, a 32 diametral pitch and a 20° pressureangle. As discussed, other rotary knife blades styles, configurations,and sizes may be used with the power operated rotary knife 100 dependingon the specific cutting/trimming application to be undertaken.

Blade Housing 400

As can best be seen in FIGS. 12, 12A, 17 and 18, in one exemplaryembodiment of the present disclosure, the blade housing 400, that is,the annular split ring 401, includes the mounting section 402 and theblade support section 450. The blade support section 450 extends aroundthe entire 360 degrees (360°) circumference of the blade housing 400,except for a circumferential discontinuity resulting from the bladehousing split 401 a. The blade support section 450, including radiallyspaced apart inner and outer walls 452, 454 of the blade support section450, is centered about a central axis or center line CBH (FIG. 17). Inassembled condition of the rotary knife blade 300 and the blade housing400, the blade housing center line CBH is substantially coincident withthe rotary knife blade central axis of rotation R. As explainedpreviously, due to the operating clearance between the rotary knifeblade 300 and the blade housing 400 and the due to load forces F1applied to the rotary knife blade 300, the blade axis of rotation R maybe slightly angled or tilted with respect the blade central axis CBH.However, under non-loaded conditions, in assembled combination 500, therotary knife blade 300 and the blade support section 450 of the bladehousing 400 are substantially connected with the rotary knife bladecentral axis of rotation R.

The inner wall 452 of the blade support section 450 includes an upperportion 452 a, adjacent an upper end 456 of the blade support section450, a middle portion 452 b, which includes the blade housing bearingregion 460, and a lower portion 452 c, adjacent a lower end 458 of theblade support section 450. The outer wall 454 of the blade supportsection 450 is substantially vertical, parallel with the blade housingcenter line CBH, with angled transition portions or chamfers adjacentthe upper and lower ends 456, 458 of the blade housing section 450. Theupper portion 452 a of the inner wall 452 is substantially vertical andparallel to the outer wall 454. The middle portion 452 b of the innerwall 452 includes the bearing race 466, defining the bearing region 460of the blade housing 400. The bearing race 466 extends radially into theinner wall 452. That is, the bearing race 466 forms a part of the innerwall 452 but extends radially inwardly with respect to a vertical wallportion or vertical extent 452 d of the inner wall 452 defined by theupper portion 452 a of the inner wall 452. The bearing race 466 extendsinto the inner wall 452 in a direction that is radially outwardly orradially away from the blade housing center line CBH. For example, theback wall portion 469 of the bearing race 466 is radially more distantfrom the blade housing center line CBH (and the blade axis of rotationR) than the vertical wall portion 452 d of the upper portion 452 a ofthe inner wall 452, while the vertical wall portion 452 d is a radiallyinnermost portion of the blade housing blade support section 450 and theblade housing 400, as measured with respect to the blade housing centerline CBH.

As can best be seen in FIG. 12A, the bearing race 466 of the bladehousing blade support section 450 includes a generally horizontallyextending upper surface 467 and an axially spaced apart generallyhorizontally extending lower surface 468. Bridging the upper and lowersurfaces 467, 468 of the bearing race 466 is the back wall portion orsurface 469, which defines the blade housing bearing surface 462. In oneexemplary embodiment, the back surface 469 of the bearing race 466 isgenerally v-shaped and includes the axially spaced apart upper and lowerangled wall portions or surfaces 466 a, 466 b connected by the vertex466 c of the bearing race 466. The upper angled surface 466 a, whenviewed in three dimensions is frustoconical, converging in a directionproceeding toward the upper end 456 of the blade housing blade supportsection 450, while the lower angled surface 466 b, when viewed in threedimensions is frustoconical, converging in a direction proceeding towardthe lower end 458 of the blade housing blade support section 450. Theupper angled surface 466 a comprises the frustoconical or angled upperbearing face 464 a of the bearing surface 462 and the lower angledsurface 466 b comprises the frustoconical or angled lower bearing face464 a of the bearing surface 462. In the present exemplary embodiment,given the arcuate shape of the blade bearing surface 322 and given thegenerally v-shape of the blade housing bearing surface 462, the upperand lower bearing faces 464 a, 464 b of the blade housing 400 areaxially separated by an axial gap corresponding to a region of thevertex 466 c of the bearing race 466. However, as would be recognized byone of skill in the art, depending on the configuration of the bladehousing bearing surface 462, e.g., an arcuate blade housing bearingsurface, there may not be an axial gap between the upper and lowerbearing faces and, indeed, the upper and lower bearing faces may extentto the vertex of the bearing race.

The lower portion 452 c of the inner wall 452 of the blade housing bladesupport section 450 includes the radially inwardly extending projection470 which forms a labyrinth seal with the annular channel 331 of theouter wall 318 of the body 310 of the rotary knife blade 300, asexplained previously. The projection 470, in one exemplary embodiment,defines a generally rectangular annular land 470. The land 470 includesan upper generally horizontal surface 472, which corresponds to thelower horizontal surface 468 of the bearing race 466, a radiallyinwardly extending V-shaped generally vertical surface 473, comprising ashort angled upper surface portion 475 and a longer angled lower surfaceportion 476, and a horizontal lower surface 477 that defines the lowerend 458 of the blade support section 450 of the blade housing 400.

The mounting section 402 of the blade housing 400 includes an inner wall404 and the radially spaced apart outer wall 406 and a first upper end408 and an axially spaced apart second lower end 410. The mountingsection 402 circumferentially overlaps and defines a portion of theannular blade support section 450, subtending an angle of approximately170°. Stated another way, the blade housing mounting section 402 extendsapproximately ½ of the way around the circumference of the blade housing400. In the region of the mounting section 402, the mounting section 402and the blade support section 450 overlap. Portions of upper end 408 ofthe mounting section 402 extend axially above the upper end 456 of theblade support section 450. Circumferentially, the mounting section 402extends between axially tapered right and left ends 412, 414 of themounting section 402. The tapered ends 412, 414 taper axially betweenthe higher upper end 408 of the mounting section 402 and the lower upperend 456 of the blade support section 450.

As can best be seen in FIG. 18, the split 401 a of the blade housing 400is in a central region 411 of the mounting section 402 extends from theinner wall 404 through the outer wall 406 of the mounting section 402 toallow for expansion or contraction of the blade housing circumferencefor purposes of increasing or decreasing the blade housing diameter BHD.In the region of the split 401 a, the upper end 408 of the mountingsection 402 includes an arcuate recesses region 408 a, which is centeredabout the split 401 a, to allow for clearance of the gear head 614 ofthe pinion gear 610. The upper end 408 of the mounting section 402includes two additional arcuate recessed regions 408 b, 408 c whichpermit clearance of respective ones of the pair of bosses 223 cextending from the back wall 223 of the clamp body 222 of the clampingassembly 220. The recessed region 408 b is circumferentially wider thanthe recessed region 408 c to allow for expansion of the blade housingdiameter while still providing clearance of the boss 223 c. As notedpreviously, the blade housing 400 includes the pair of circumferentialpry slots 430 formed in the outer wall 406 of the mounting section 402which facilitate allowing an operator of the power operated rotary knife100 to easily expand the diameter of the blade housing 400 for eitherchanging the operating/running clearance of the rotary knife blade 300within the blade housing 400 or for the purpose of changing the rotaryknife blade 300, as previously explained, while still keeping theblade—blade housing combination 500 secured to the frame body arcuatemounting pedestal 252.

When the blade housing mounting section 402 is seated in the seatingregion 252 a of the frame body 250, the rearward clamping surface 224 ofthe clamp body 222 seats against the frame mounting pedestal 252.Specifically, the arcuate outer surfaces 223 d of the pair of bosses 223c of the rear wall 223 of the clamp body 222 seat and bear againstcorresponding arcuate recesses 252 b of the forward wall 251 of theframe body 250. The mounting section 402 is thereby trapped between therearward wall 223 of the clamp body 222 and the seating region 252 a ofthe arcuate mounting pedestal 252 of the forward wall 251 a of the framebody 250 and the blade—blade housing combination 500 is secured to theframe body 250.

As can best be seen in FIGS. 11, 12, 12A and 17-18, the blade supportsection 450 includes the annular inner wall 452 and the radially spacedapart annular outer wall 454. The blade support section 450 furtherincludes a generally planar first upper end 456 and an axially spacedgenerally planar second lower end 458. The blade support section 450extends about the entire 360° circumference of the blade housing 400,except for the circumferential discontinuity resulting from the bladehousing split 401 a. The blade support section 450 in a region of themounting section 402 is continuous with and the blade support sectioninner wall 452 forms a portion of the inner wall 404 of the mountingsection 402. As can be seen in FIG. 18, a portion 404 a of the innerwall 404 of the mounting section 402 of the blade housing 400 within thehorizontally extending dashed lines IWBS constitutes both a part of theinner wall 404 of the mounting section 402 and a part of the of theinner wall 452 of the blade support section 450. That is, the inner wall404 of the mounting section 402 is coincident with the inner wall 452 ofthe blade support section 450. The dashed lines IWBS substantiallycorrespond to an axial extent of the inner wall 452 of the blade supportsection 450, that is, the lines IWBS correspond to the upper end 456 andthe lower end 458 of the blade support section 450.

The friction or drag experienced by the operator as the power operatedrotary knife 100 is manipulated by the operator to move through aproduct is dependent, among other things, on the cross sectional shapeor configuration of the blade—blade housing combination 500 in a cuttingregion CR of the assembled combination 550. The blade—blade housingcombination 500 is configured and contoured to be as smooth andcontinuous as practical. As a layer of material is cut or trimmed from aproduct being processed (for example, a layer of tissue or a layer ofmeat or fat trimmed from an animal carcass) by moving the power operatedrotary knife 100 in a cutting direction such that the rotating knifeblade 300 and blade housing 400 move along and through the product tocut or trim the layer of material. As the power operated rotary knife100 is moved by the operator, the blade edge 361 cuts the layer forminga cut portion of the layer. The cut portion moves along a cut or trimmedmaterial path of travel through the cutting opening CO of theblade—blade housing combination 500 as the power operated rotary knife100 advances through the product.

A new outer surface layer is formed as the layer is cut away from theproduct. The cut portion of the layer slides along the inner walls 366,316 of the blade section 360 and body 310 of rotary knife blade 300,while new outer surface layer slides along the respective outer walls368, 454 of the blade section 360 of the knife blade 300 and the bladesupport section 450 of the blade housing 400. The blade—blade housingcombination 500 in the cutting region CR is shaped to extent possible toreduce drag and friction experienced by the operator when manipulatingthe power operated rotary knife 100 in performing cutting or trimmingoperations.

The blade—blade housing structure 500 of the present disclosure and theother features, characteristics and attributes, as described above, ofthe power operated rotary knife 100 may be used with a variety of rotaryknife blade styles, configurations, and sizes and corresponding bladehousings. As mentioned above, the exemplary rotary knife blade 300 is ahook blade style rotary knife blade. Numerous other blade styles,including, but not limited to, flat and straight style blades andcombinations of blade styles may be utilized, with an appropriate bladehousing, in the power operated rotary knife 100 of the presentdisclosure, as would be understood by one of skill in the art. It is theintent of the present disclosure to cover all such rotary knife bladestyles and sizes, together with the corresponding blade housings, thatmay be used in the power operated rotary knife 100.

In one exemplary embodiment, the hand piece 120 and the elongatedcentral core 152 of the handle assembly 110 may be fabricated of plasticor other material or materials known to have comparable properties andmay be formed by molding and/or machining. The hand piece 120, forexample, may be fabricated of two over molded plastic layers, an innerlayer comprising a hard plastic material and an outer layer or grippingsurface comprised of a softer, resilient plastic material that is morepliable and easier to grip for the operator. The frame body 250 of thehead assembly 200 may be fabricated of aluminum or stainless steel orother material or materials known to have comparable properties and maybe formed/shaped by casting and/or machining. The rotary knife blade 300and blade housing 400 may be fabricated of a hardenable grade of alloysteel or a hardenable grade of stainless steel, or other material ormaterials known to have comparable properties and may be formed/shapedby machining, forming, casting, forging, extrusion, metal injectionmolding, and/or electrical discharge machining or another suitableprocess or combination of processes.

Second Embodiment—Power Operated Rotary Knife 1000

A second exemplary embodiment of a power operated rotary knife of thepresent disclosure is shown generally at 1000 in FIGS. 21 -25. The poweroperated rotary knife 1000 includes an elongated handle assembly 1110, ahead assembly 1200, releasably secured to a forward or distal end of thehandle assembly 1110, and a drive mechanism 1600, including a gear train1604. The power operated rotary knife 1000 extends between a distal orforward end 1001 and a proximal or rearward end 1002 of the knife 1000.The head assembly 1200 includes a frame body 1250 and clamping assembly1220 which secures an assembled blade—blade housing combination 1500 tothe frame body 1250. The assembled blade—blade housing combination 1500includes an annular rotary knife blade 1300 and an annular blade housing1400 supporting the rotary knife blade 1300 for rotation about theblade's central axis of rotation R.

The elongated handle assembly 1110 is substantially similar to thehandle assembly 110 of the power operated rotary knife 100 of the firstexemplary embodiment. The handle assembly 1110 extends along alongitudinal axis LA and includes a handle assembly throughbore 1115.The longitudinal axis LA of the handle assembly 1110 extends through acenter of the elongated throughbore 1115 and is orthogonal to andintersects the rotary knife blade central axis of rotation R. The drivemechanism 1600 and gear train 1604 are substantially similar to thedrive mechanism 600 and gear train 604 of the power operated rotaryknife 100 of the first exemplary embodiment. The frame body 1250 and theclamping assembly 1220 of the head assembly 1200 are substantiallysimilar to the frame body 250 and the clamping assembly 220 of the headassembly 200 of the power operated rotary knife 100 of the firstexemplary embodiment. Various components and assemblies of the poweroperated rotary knife 1000 are substantially similar in structure and/orfunction to corresponding components and assemblies of the poweroperated rotary knife 100, as previously described. In the interest ofbrevity, components and assemblies of the power operated rotary knife1000 that are similar to the corresponding components and assemblies ofthe power operated rotary knife 100 of the first exemplary embodiment instructure and/or function will not be fully described herein. Instead,reference is made to the description of such components and assembliesset forth above in connection with the power operated rotary knife 100,as set forth above. Materials/fabrication of components and assembliesof the power operated rotary knife 1000 an similar tomaterials/fabrication of corresponding components and assemblies of thepower operated rotary knife 100, as described above. Such descriptionsof components and assemblies of the power operated rotary knife 100 ofthe first exemplary embodiment are hereby incorporated by reference inthe following description of the power operated rotary knife 1000 of thesecond exemplary embodiment. Identification of axes, lines, planes anddirections for the power operated rotary knife 1000, as set forthherein, will be the same as used for the description of the poweroperated rotary knife 100 of the first exemplary embodiment.

The annular rotary knife blade 1300 (FIG. 23) of the power operatedrotary knife 1000 is substantially similar in structure and function tothe rotary knife blade 300 of the power operated rotary knife 100 of thefirst exemplary embodiment and includes an annular body 1310 and a bladesection 1360 extending from the body 1310, substantially similar to theannular body 310 and the blade section 360 of the rotary knife blade300. The annular rotary knife blade 1300 includes a driven gear 1340,substantially similar in structure and function to the driven gear 340of the annular rotary knife blade 300, and a bearing region 1320,substantially similar in structure and function to the bearing region320 of the annular rotary knife blade 300. An outer wall 1316 of thebody 1310 of the rotary knife blade 1300 includes an arcuate surface1319. The arcuate surface 1319 defines both a bearing surface 1322 ofthe bearing region 1320 and defines an outer surface 1340 b of a drivengear 1340, substantially similar in structure and function to thearcuate surface 319 of the outer wall 316 of the body 310 of the annularrotary knife blade 300 of the first exemplary embodiment.

Blade Housing 1400

As best seen in FIGS. 24 and 25, the blade housing 1400 comprises anannular split ring 1401 and includes a mounting section 1402 and a bladesupport section 1450. The blade support section 1450 extends around theentire 360 degrees (360°) circumference of the blade housing 1400,except for a circumferential discontinuity resulting from the bladehousing split. The blade support section 1450, including radially spacedapart inner and outer walls 1452, 1454 of the blade support section1450, is centered about a central axis or center line CBH. In assembledcondition of the rotary knife blade 300 and the blade housing 400, theblade housing center line CBH is substantially coincident with therotary knife blade central axis of rotation R.

As best seen in FIG. 24, the mounting section 1402 of the annular bladehousing 1400 is substantially similar in structure and function to themounting section 402 of the annular blade housing 400 of the poweroperated rotary knife 100. With regard to the blade support section1450, however, a bearing region 1460 of the blade support section 1450is different than the bearing region 460 of the blade support section450 of the blade housing 400 of the first exemplary embodiment. As such,a blade—blade housing bearing structure 1550 is different than theblade—blade housing bearing structure 550 of the power operated rotaryknife 100 of the first exemplary embodiment. Specifically, as best seenin FIG. 25, like the annular bearing race 466 of the inner wall 452 ofthe blade support section 450 of the blade housing 400, a bearing region1460 of a blade support section 1450 of the blade housing 1400 includesan annular bearing race 1466 extending radially into an inner wall 1452of the blade support section 1450. However, unlike the bearing race 466of the blade support section 450 of the blade housing 400 of the poweroperated rotary knife 100 of the first embodiment, the annular bearingrace 1466 includes a back wall 1469 defining a continuous concave,arcuate surface 1466 a characterized by a constant radius of curvatureBRRAD. By concave, it is meant that the concave arcuate surface 319 bowsinwardly, that is, in a radial direction away from the blade housingcenter line CBH and away from an extent of the upper and lower portions452 a, 452 c of the inner wall 452 toward the outer wall 454 of theblade support section 450. Stated another way, the concave arcuatesurface 319 bows radially away from the blade housing center line CBH ina direction toward the outer wall 454 of the blade support section 450.As shown schematically in FIG. 25, the radius of curvature BRRAD of thearcuate surface 1466 a is characterized by center of curvature or centerpoint BRCPT having a constant radius BRRD, as opposed to a pair ofangled surfaces 466 a, 466 b of the blade housing bearing race 466 ofthe first exemplary embodiment.

The bearing race 1466 includes a generally horizontally extending uppersurface 1467 and an axially spaced apart generally horizontallyextending lower surface 1468. Bridging the upper and lower surfaces1467, 1468 of the bearing race 1466 is the back wall portion or surface1469 of the bearing race 1466 which includes the continuous concave,arcuate surface 1466 a. The continuous concave, arcuate surface 1466 aof the back wall portion 1469 of the blade housing bearing race 1466,when viewed In three dimensions, includes an upper arcuate or curvedsurface 1466 d, extending above an intermediate portion 1466 c of thebearing race 1466, and a lower arcuate or curved surface 1466 e of thearcuate surface 1466 a, extending below the intermediate portion 1466 cof the arcuate surface 1466 a. The intermediate portion 1466 c includesa vertex location or a midpoint location 1466 k of the arcuate surface466 a which, as can best be seen in FIG. 25, represents a location thatis radially furthest away from the blade housing central axis or centerline CBH. The upper curved surface 1466 d converges in a directionproceeding toward the upper end 1456 of the blade housing blade supportsection 1450, while the lower curved surface 1466 e converges in adirection proceeding toward a lower end 1458 of the blade housing bladesupport section 1450. That is, the upper and lower curved surfaces 1466d, 1466 e of the back wall surface 1469 have arcuate or curved, asopposed to linear, side walls.

The arcuate surface 1466 a of the back wall 1469 of the bearing race1466 defines an arcuate bearing surface 1462 comprising an upper arcuatebearing face 1464 a, extending above the midpoint location 1466 k, and alower arcuate bearing face 1464 b, extending below the midpoint location1466 k. The upper arcuate bearing face 1464 a substantially correspondsto the upper curved surface 1466 d and the lower arcuate bearing face1464 b corresponds to the lower curved surface 1466 e. The upper andlower bearing faces 1464 a, 1464 b are part of a continuous concavearcuate surface defined by the arcuate surface 1466 a of the back wall1469 of the bearing race 1466 and that intersect at the intermediateportion 1466 c of the arcuate surface 1466 a of the bearing race 1466characterized by the radius of curvature BBRAD and the center pointBRCPT. The midpoint location 1466 k of the intermediate portion 1466 cis a center location of the annular bearing race 1466 that radiallyfurthest away from the blade housing central axis or center line CBH.Since the bearing race 1466 is annular, when viewed in three dimensions,the midpoint location 1466 k defines a circular line that is centeredabout the blade housing center line CBH. When viewed in longitudinalsection in two dimensions, the upper bearing face 1464 a and lowerbearing face 1464 b define arcuate upper and lower arcuate bearing lines1465 a, 1465 b that would intersect in the intermediate portion 1466 c.The center point BRCPT of the radius of curvature BRRAD of the arcuatesurface 1466 a is radially aligned along a horizontally extendingstraight or radius line RL1 (FIG. 25) extending orthogonally from theblade housing central line CBH to the midpoint location 1466 c of theintermediate portion 1466 c of the arcuate surface 1466 a. If the bladeaxis of rotation R and the blade housing center line CBH are aligned,the radius line RL1 would be substantially coincident with the bladerotational plane RP.

To avoid binding between the blade bearing region 1320 and the bladehousing bearing region 1460, advantageously, the radius of curvatureBRRAD of the arcuate surface 1466 a of the back wall 1469 of the bladehousing bearing race 1466 is greater than the corresponding radius ofcurvature RAD of the arcuate surface 319 of the outer wall 318 of therotary knife blade body 310. In one exemplary embodiment, the radius ofcurvature BRRAD of the arcuate surface 1466 a of the back wall 1469 ofthe bearing race 1466 of the blade housing blade support section 1450 is0.052 in., while the radius of curvature RAD of the arcuate surface 319of the outer wall 318 of the rotary knife blade body 310 is 0.047 in.,approximately 0.005 in. smaller radius. Advantageously, the closematching of the arcuate bearing surfaces 1322, 1462 of the rotary knifeblade 1300 and the blade housing 1400 provide a greater potentialbearing contact area which, under certain conditions, may result in areduced wear rate for the respective bearing surfaces 1322, 1462.Advantageously, a reduction in wear rate of the bearing region 1320 ofthe rotary knife blade 1300 and/or a reduction in wear rate of thebearing region 1460 of the blade support section 1450 of the bladehousing tends to increase working time intervals between operatoradjustments to a blade housing diameter BHD of the blade support section1450 of the blade housing 1400 to account for looseness of the rotaryknife blade 1300 as it rotates within the blade support section 1450 ofthe blade housing 1400. Increasing working time intervals betweenoperator adjustments to the blade housing diameter BHD increasesoperator productivity and decreases downtime.

Further, the advantages of the axially and radially overlappingstructure or configuration of the driven gear 1340 and the bearingsurface 1322 of the rotary knife blade 1300 of the present disclosurewhich, under certain use conditions, may advantageously reduce the gearreaction forces Fn3, Fn4 resulting from the gear force Fg and may, undercertain us conditions, advantageously provide for a reduced wear rate ofthe bearing region 1322 of the rotary knife blade 1300 and/or reducedwear rate of the driven gear 1340 and/or reduced wear rate of the piniongear 1610, as explained with respect to the power operated rotary knife100 of the first exemplary embodiment, are equally applicable to therotary knife blade 1300, the blade housing 1400, and the pinion gear1610 of the second exemplary embodiment of the power operated rotaryknife 1000.

In one exemplary embodiment of the present disclosure, the blade housing1400 is an annular split ring 1401, including the mounting section 1402and the blade support section 1450. The blade support section 1450extends around the entire 360 degrees (360°) circumference of the bladehousing 1400, except for a circumferential discontinuity resulting fromthe blade housing split. The mounting section 1402 is substantiallysimilar to the mounting section 402 of the annular blade housing 400 ofthe first exemplary embodiment. The blade support section 1450, whichincludes radially spaced apart inner and outer walls 1452, 1454 andaxially spaced apart upper and lower ends 1456, 1458, is centered abouta central axis or center line CBH. In assembled condition of the rotaryknife blade 1300 and the blade housing 400, the blade housing centerline CBH is substantially coincident with the rotary knife blade centralaxis of rotation R. As explained previously with regard to the firstexemplary embodiment, due to the operating clearance between the rotaryknife blade 1300 and the blade housing 1400 and the due to load forcesF1 applied to the rotary knife blade 1300, the blade axis of rotation Rmay be slightly angled or tilted with respect the blade central axisCBH. However, under non-loaded conditions, in assembled combination1500, the rotary knife blade 1300 and the blade support section 1450 ofthe blade housing 1400 are substantially concentric with the rotaryknife blade central axis of rotation R.

The inner wall 1452 of the blade support section 1450 includes an upperportion 1452 a, adjacent the upper end 1456 of the blade support section1450, a middle portion 1452 b, which includes the blade housing bearingregion 1460, and a lower portion 1452 c, adjacent the lower end 1458 ofthe blade support section 1450. The outer wall 1454 of the blade supportsection 1450 is substantially vertical and parallel with the bladehousing center line CBH, with angled transition portions or chamfersadjacent the upper and lower ends 1456, 1458 of the blade housingsection 1450. The upper portion 1452 a of the inner wall 1452 defines avertical wall portion or vertical extent 1452 d that is substantiallyvertical and parallel to the outer wall 1454. The middle portion 1452 bof the inner wall 1452 includes the blade housing bearing race 1466,defining the bearing region 1460 of the blade housing 1400. The bearingrace 1466 extends radially into the inner wall 1452. That is, thebearing race 1466 extends into the inner wall 1452 in a direction thatis radially outwardly or radially away from the blade housing centerline CBH. For example, the back wall portion 1469 of the bearing race1466 is radially more distant from the blade housing center line CBH(and the rotary knife blade axis of rotation R) than the vertical wall1452 d of the upper portion 1452 a of the inner wall 1452.

The arcuate surface 1466 a of the bearing race 1466 defines the bladehousing bearing surface 1462. The arcuate bearing surface 1462 includesthe upper arcuate bearing face 1464 a, extending above the radiallyinnermost location or vertex or midpoint 1466 c of the arcuate surface1466 a of the bearing race 1466, and the lower arcuate bearing face 1464b, extending below the midpoint 1466 c of the arcuate surface 1466 a ofthe bearing race 1466. In the present exemplary embodiment, given thearcuate shape of the blade bearing surface 1322 and given the matchingarcuate shape of the blade housing bearing surface 1462, the upper andlower bearing faces 1464 a, 1464 b of the blade housing 1400 extend froma common point or location, namely, the midpoint 1466 c of the arcuatesurface 1466 a of the back wall 1469 of the bearing race 1466. As partof the blade—blade housing bearing structure 1550, the upper arcuatebearing face 1324 a of the bearing surface 1322 of the rotary knifeblade 1300 slidingly engages and bears against the upper arcuate orcurved bearing face 1464 a of the bearing surface 1464 of the bladehousing 1400, while the lower arcuate bearing face 1324 b of the bearingsurface 1322 of the rotary knife blade 1300 slidingly engages and bearsagainst the lower arcuate or curved bearing face 1464 b of blade housingbearing surface 1462, to rotatably support and position the rotary knifeblade 1300 with respect to the annular blade housing 1400 and define arotational plane RP of the blade 1300.

The lower portion 1452 c of the inner wall 1452 of the blade housingblade support section 1450 includes the radially inwardly extendingprojection 1470 which forms a labyrinth seal with the annular channel1331 of the outer wall 1318 of the body 1310 of the rotary knife blade1300. The projection 1470, in one exemplary embodiment, defines agenerally rectangular annular land 1470. The land 1470 includes an uppergenerally horizontal surface 1472, which corresponds to the lowerhorizontal surface 1468 of the bearing race 1466, a radially inwardlyextending V-shaped generally vertical surface 1473, comprising a shortangled upper surface portion 1475 and a longer angled lower surfaceportion 1476, and a horizontal lower surface 1477 that defines the lowerend 1458 of the blade support section 1450 of the blade housing 1400.

The blade—blade housing structure 1550 of the present disclosure and theother features, characteristics and attributes, as described, above, ofthe power operated rotary knife 1000 may be used with a variety ofrotary knife blades styles, configurations, and sizes and correspondingblade housings. The exemplary rotary knife blade 1300 is a hook bladestyle rotary knife blade. Numerous other blade styles, including, butnot limited to, flat and straight style blades and combinations of bladestyles may be utilized, with an appropriate blade housing, in the poweroperated rotary knife 1000 of the present disclosure, as would beunderstood by one of skill in the art. It is the intent of the presentdisclosure to cover all such rotary knife blade styles and sizes and thecorresponding blade housings, that may be used in the power operatedrotary knife 1000.

Third Embodiment—Power Operated Rotary Knife 2000

A third exemplary embodiment of a power operated rotary knife of thepresent disclosure is shown generally at 2000 in FIGS. 26-30A. The poweroperated rotary knife 2000 includes an elongated handle assembly 2110,the head assembly 2200, releasably secured to a front or distal end ofthe handle assembly 2110, and a drive mechanism 2600, including a geartrain 2604. The power operated rotary knife 2000 extends between adistal or forward end 2001 and a proximal or rearward end 2002 of theknife 1000. The head assembly 2200 includes a frame body 2250 andclamping assembly 2220 which secures an assembled blade—blade housingcombination 2500 to the frame body 2250. The assembled blade—bladehousing combination 2500 includes an annular rotary knife blade 2300 andan annular blade housing 2400 supporting the rotary knife blade 2300 forrotation about an axis of rotation R.

The handle assembly 2110 is substantially similar to the handle assembly110 of the power operated rotary knife 100 of the first exemplaryembodiment. The elongated handle assembly 2110 extends along alongitudinal axis LA and includes a handle assembly throughbore 2115.The longitudinal axis LA of the handle assembly 2110 extends through acenter of the throughbore 2115 and is orthogonal to and intersects therotary knife blade central axis of rotation R. The drive mechanism 2600and the gear train 2604 are substantially similar to the drive mechanism600 and gear train 604 of the power operated rotary knife 100 of thefirst exemplary embodiment. The frame body 2250 and the clampingassembly 2220 of the head assembly 2200 are substantially similar to theframe body 250 and the clamping assembly 220 of the head assembly 200 ofthe power operated rotary knife 100 of the first exemplary embodiment.Various components and assemblies of the power operated rotary knife2000 are substantially similar in structure and/or function tocorresponding components and assemblies of the power operated rotaryknife 100 and/or the power operated rotary knife 1000, as previouslydescribed. In the interest of brevity, components and assemblies of thepower operated rotary knife 2000 that are similar to the correspondingcomponents and assemblies of the power operated rotary knife 100 of thefirst exemplary embodiment and/or the power operated rotary knife 1000of the second exemplary embodiment in structure and/or function will notbe fully described herein. Instead, reference is made to the descriptionof such components and assemblies set forth above in connection with thepower operated rotary knife 100 and the power operated rotary knife1000, as set forth above. Materials/fabrication of components andassemblies of the power operated rotary knife 2000 are similar tomaterials/fabrication of corresponding components and assemblies of thepower operated rotary knife 100, as described above. Such descriptionsof components and assemblies of the power operated rotary knife 100 ofthe first exemplary embodiment and/or the components and assemblies ofthe power operated rotary knife 1000 of the second exemplary embodimentare hereby incorporated by reference in the following description of thepower operated rotary knife 2000 of the third exemplary embodiment.Identification of axes, lines, planes and directions for the poweroperated rotary knife 2000, as set forth herein, will be the same asused for the description of the power operated rotary knife 100 of thefirst exemplary embodiment and/or the power operated rotary knife 1000of the second exemplary embodiment.

The differences between the power operated rotary knife 2000 of thethird exemplary embodiment and the power operated rotary knives 100,1000 of the first and second exemplary embodiments, resides primarily inthe configuration of respective blade—blade housing bearing structures2550, 1550, 550. Specifically, in the blade—blade housing bearingstructure 2550 of the power operated rotary knife 2000, there are twobearing structures, namely, a first blade—blade housing bearingstructure 2560 and a second blade—blade housing hearing structure 2570.The first blade—blade housing bearing structure 2560. in one exemplaryembodiment, is substantially similar in structure and function to theblade—blade housing bearing structure 1550 of the power operated rotaryknife 1000 of the second exemplary embodiment. The first blade—bladehousing bearing structure 2560 comprises the convex bearing surface 2322of the rotary knife blade 2300 and the concave bearing surface 2462 ofthe blade support section 2450 of the blade housing 2400, substantiallysimilar to the convex bearing surface 322 of the rotary knife blade 300and the concave bearing surface 462 of the blade housing blade supportsection 450.

The second blade—blade housing bearing structure 2570 (FIG. 28), spacedaxially below the first blade—blade housing bearing structure 2560,includes a radially inwardly extending or concave bearing race 2380formed in an outer wall 2318 of a body 2310 of the rotary knife blade2300 which engages and bears against a convex protruding bearing bead2480 of an inner wall 2452 of the blade support section 2450 of theannular blade housing 2400 during operation of the power operated rotaryknife 2000. Specifically, the protruding bearing bead 2480 of the innerwall 2452 of the blade support section 2450 defines a second arcuatebearing surface 2482 of the blade housing 2400, the second arcuatebearing surface 2482 being convex with respect to the inner wall 2452and extending in a direction of a center line CBH of the blade supportsection 2450 of the blade housing 2400. The bearing race 2380 of theouter wall 2318 of the blade body 2310 defines the second arcuatebearing surface 2382 of the bearing region 2320 of the rotary knifeblade 2300, the second arcuate bearing surface 2382 being concave withrespect to the outer wall 2318 of the body 2310 of the rotary knifeblade 2300 and extending in a direction toward the blade central axis ofrotation R. The concave bearing race 2380 of the blade body 2310 extendsalong the outer wall 2318 of the body 2310 in a radial direction towardthe blade central axis of rotation R from an upper end portion 2381 c,through an intermediate portion 2381 d and terminates at a lower endportion 2381 e of the bearing race 2380. The intermediate portion 2381 dof the bearing race 2380 defines a radially innermost midpoint locationor intermediate location 2381 k of the bearing race 2380 and, in oneexemplary embodiment, defines a radially innermost location of the outerwall 2318 of the body 2310. The bearing race 2380 includes an arcuateupper region 2381 a extending between the upper end portion 2381 c andthe intermediate portion 2381 d and an arcuate lower region 2381 bextending between the intermediate portion 2381 d and the lower endportion 2381 e. The second bearing surface 2382 includes an arcuateupper bearing face 2384 a in the arcuate upper region 2381 a of thebearing race 2380 disposed above the midpoint location 2381 k andfurther includes an arcuate lower bearing face 2384 b in the arcuatelower region 2381 b of the bearing race 2380. The second bearing surface2382 of the bearing race 2380 is defined by a concave arcuate surface2380 a of the bearing race 2380 which is part of a concave centralportion 2385 of the bearing race 2380. The concave central portion 2385includes the arcuate upper and lower regions 2381, 2381 b, as describedabove.

Advantageously, the addition of the second blade—blade housing bearingstructure 2570, under certain operating conditions and parameters,including load and gear forces applied to the blade 2300, may reduce thewear rate experienced by a bearing region 2320 of the rotary knife blade2300 and/or a bearing region 2460 of a blade support section 2450 of theblade housing 2400. Equally advantageously, if the wear rate for therotary knife blade 2300, including the bearing region 2320, as well asother wear areas of the blade 2300, and blade housing, including thebearing region 2460, are below a desired or target wear rate, bladerotational speed may be increased by a designer until the blade andblade housing wear rates approach the respective target wear rates. Suchan increase in blade rotational speed provides for advantages of reducedoperator effort for cutting and trimming operations and longer timebetween blade sharpenings, as discussed above. Additionally, reducingthe wear rate experienced by the bearing region 2320 of the rotary knifeblade 2300 and/or the bearing region 2460 of the blade housing bladesupport section 2450 may also advantageously tend to increase workingtime intervals between operator adjustments to a circumference of theblade housing 2400 to reduce a blade housing diameter BHD of the bladesupport section 2450 of the blade housing 2400 to tighten the bladehousing blade support section 2450 about the rotary knife blade 2300 asthe blade 2300 within the blade support section 2450. Increasing workingtime intervals between operator adjustments to the blade housingdiameter BHD increases operator productivity and decreases downtime.

In one exemplary embodiment of the power operated rotary knife 2000, thesecond blade—blade housing bearing structure 2570, replaces thelabyrinth seal formed by the interfitting of the annular channel 331 ofthe middle portion 318 b of the outer wall 318 of the body 310 of therotary knife blade 300 and the radially projecting annular land 471 ofthe inner wall 452 of the blade support section 450 of the blade housing400 of the power operated rotary knife 100 of the first exemplaryembodiment. Specifically, the annular channel 331 of the middle portion318 b of the body 310 of the rotary knife blade 300 of the firstembodiment is replaced by the bearing race 2380 forming a lower portion2318 b of the outer wall 2318 of the body 2310 of the rotary knife blade2300 of the third exemplary embodiment. The bearing race 2380 whichforms part of the outer wall 2318 extends radially into an extent of theouter wall 2318, as, for example, defined by a vertical section 2318 dof a lower portion 2318 c of the outer wall 2318, in a direction towardthe blade central axis of rotation R. A central portion 2384 of thebearing race 2380 extending between the upper end portion 2381 c and thelower end portion 2381 e includes an arcuate surface 2380 a. The arcuatesurface 2380 defines the second concave arcuate bearing surface 2382 ofthe rotary knife blade bearing region 2320 and is part of the secondblade—blade housing bearing structure 2570. Similarly, the annular land471 of the middle portion 452 b of the inner wall 452 of the bladesupport section 450 of the blade housing 400 is replaced by bearing bead2480 forming a middle portion 2452 b of an inner wall 2452 of the bladehousing blade support section 2450. In a central portion 2485, thebearing bead 2480 includes a convex arcuate surface 2480 a. The convexarcuate surface 2480 a defines the second convex arcuate bearing surface2482 of the blade housing bearing region 2460 and is part of the secondblade—blade housing bearing structure 2570.

The reason that the addition of the second blade—blade housing bearingstructure 2570 to the assembled combination 2500 of the rotary knifeblade 2300 and the annular blade housing 2400, under certain operatingand load conditions, contributes to lower wear rate for the bladebearing region 2320 and the blade housing bearing region 2460, ascompared to, for example, the wear rate for the blade bearing region 320of the rotary knife blade 300 and the blade housing bearing region 460of the blade housing 400 of the power operated rotary knife 100 of thefirst exemplary embodiment is as follows. As schematically illustratedin FIG. 28, assume that a load force applied to the rotary knife blade2300 can be considered as a load force vector F1 that is applied at anangle β to a cutting edge 2361 of the blade section 2360 of the rotaryknife blade 2300. Further assume that the load force vector F1 issubstantially identical in direction and magnitude force to the loadforce vector F1 applied at an angle β to the cutting edge 361 of theblade section 360 of the rotary knife blade 300 (as schematicallyillustrated in FIG. 11). For this explanation, assume that theconfiguration of the two rotary knife blades 2300, 300 are identicalwith respect to all aspects except for the addition of the secondblade—blade housing bearing structure 2570 in the rotary knife blade2300, even though it is recognized, of course, that the annular rotaryknife blade 2400 depicted in the third exemplary embodiment is astraight style blade, as opposed to a hook style blade of the annularrotary knife blade 300 of the first exemplary embodiment.

As was the case with the power operated rotary knife 100, operatingclearance is provided between the rotary knife blade 2300 and the bladehousing 2400 resulting in the teeter-totter or tilting effect of theblade 2300 within the blade housing 2400 when a load force vector F1 isapplied at a given location of the blade cutting edge 2361, as explainedpreviously. Viewing the reaction forces experienced by the rotary knifeblade 2300 resulting from bearing region 2320 of the rotary knife blade2300 being urged against corresponding the bearing region 2460 of theblade support section 2460 of the blade housing 2400 due the applicationof the load force vector F1, it can be seen that, because of theaddition of the second blade—blade housing bearing structure 2370, thetwo reaction force vectors, schematically depicted as Fn1, Fn2 in FIG.11, in the rotary knife blade 300 of the first exemplary embodiment arenow divided into four reaction force vectors labeled Fn1 a, Fn1 b, Fn2a, Fn2 b in FIGS. 28. That is, as experienced by the blade 2300, thefirst reaction force vector Fn1 is split between two reaction forcevectors Fn1 a, Fn1 b experienced by the blade 300. Similarly, asexperienced by the blade 2300, the second reaction force vector Fn2 issplit between two reaction force vectors Fn2 a, Fn2 b.

With the rotary knife blade 2300, a vertical or axial distance Y1′ (FIG.28) between the blade cutting edge 2361 and a location where the firstreaction force vector Fn1 a is applied to the lower bearing face 2384 bof the second bearing surface 2382 of the blade 2300 is less than avertical distance Y1 (FIG. 11) between the blade cutting edge 316 and alocation where the first reaction force vector Y1 is applied to theupper bearing face 324 a of the bearing surface 322 of the blade 2300.Similarly, with the rotary knife blade 2300, a vertical or axialdistance Y2′ (FIG. 28) between the blade cutting edge 2361 and alocation where the second reaction force vector Fn2 a is applied to theupper bearing face 2384 a of the second bearing surface 2382 of theblade 2300 is less than a vertical distance Y2 (FIG. 11) between theblade cutting edge 316 and a location where the first reaction forcevector Y2 is applied to the lower bearing face 324 b of the bearingsurface 322 of the blade 2300. Accordingly, in the rotary knife blade2300, since at least a portion of the reaction force vectors Fn1, Fn2,namely, reaction force vectors Fn1 a, Fn2 a, are acting at vertical oraxial distances (Y1′, Y2′) between the load force vector F1 and thereaction forces vectors that are less than the corresponding verticaldistances (Y1, Y2) between the load force vector F1 and the reactionforce vectors Fn1, Fn2, this results in a smaller torque or moment offorce experienced by the rotary knife blade 2300 as a result of the loadforce F1, as compared to the torque or moment of force experienced bythe rotary knife blade 300 as a result of the substantially identicalload force F1. Additionally, the reaction force Fn1 is now sharedbetween two different bearing surfaces, namely, the upper bearing face2324 a of the first bearing surface 2322 (receiving reaction forcevector Fn1 b) and the lower bearing face 2384 b of the second bearingsurface (receiving reaction force vector Fn1 a), while the reactionforce Fn2 is now shared between two different bearing surfaces, namely,the lower bearing face 2324 b of the first bearing surface 2322(receiving reaction force vector Fn2 b) and the upper bearing face 2384a of the second scaring surface 2382 (receiving reaction force vectorFn2 a). By splitting the load reaction forces Fn1, Fn2, the reactionforces experience by each of the four hearing faces 2324 a, 2324 b, 2384a, 2384 b is reduced, thus, effectively reducing the wear rate of eachof the bearing faces. The combination of reduced torque or moment offorce applied to the blade and the splitting of the reactions forceseffectively reduces the wear rate of the bearing region 2320 of therotary knife blade 2300.

The same reasoning applies equally to the reaction forces experienced bythe blade housing bearing region 2460 of the annular blade housing 2400,resulting from application of the load force vector F1 to the blade2300, as compared to the reaction forces experienced by the bladehousing bearing region 360 of the annular blade housing 400, resultingfrom application of the load force vector F1 to the blade 300. As such,under certain operating conditions and parameters, including load andgear forces applied to the blade 2300, may reduce the wear rateexperienced by the bearing region 2320 of the rotary knife blade 2300and/or the bearing region 2460 of a blade support section 2450 of theblade housing 2400, as discussed previously. Also, as mentionedpreviously, lower wear rates of the respective blade and blade housingbearing regions 2320, 2460 will also advantageously increase the timebetween operating adjustments of blade housing circumference.Adjustments to the blade housing circumference are required when theoperator senses excessive movement or play of the rotary knife blade2300 within the blade housing 2400 during operation which is typicallymanifested to the operator through increased vibration of the poweroperated rotary knife 2000 during operation of the knife. One source ofsuch undesirable movement or play is caused by wear of the blade andblade housing bearing regions 2320, 2460 as the power operated rotaryknife 2000 is operated, which causes the rotary knife blade 2300 torotate more and more loosely within the blade housing 2400 as bearingwear continues. All other things being equal, the lower the bearingregion wear rates of the rotary knife blade 2300 and the blade housing2400, advantageously, the longer the operating time period between bladehousing circumference adjustments made by the operator, leading to lessdown time and greater operator productivity. Finally, lower wear ratesof the bearing regions 2320, 2460 of the rotary knife blade 2300 and theblade housing 2400 tends to reduce premature wear of respective meshinggear teeth of a pinion gear 2610 of the gear train 2604 and the drivengear 2340 of the rotary knife blade 2300. Wear of the bearing regions2320, 2460 of the rotary knife blade 2300 and the blade housing 2400tends to cause separation between the meshing gear teeth of the piniongear 2610 and the driven gear 2340. Such separation of the meshing gearteeth may result in premature wear of the respective gear teeth of thepinion gear 2610 and the driven gear 2340. Lower wear rates of thebearing regions 2320, 2460 of the rotary knife blade 2300 and the bladehousing 2400 militates against such separation of the meshing gear teethand tends to reduce premature wear of the pinion gear 2610 of the geartrain 2604 and the driven gear 2340 of the rotary knife blade 2300.

Rotary Knife Blade 2300

The annular rotary knife blade 2300 (FIG. 29) of the third exemplaryembodiment includes the body 2310 and the blade section 2360 extendingfrom the body 2310. The rotary knife blade 2300 includes an upper end orfirst end 2302 and an axially spaced apart lower end or second end 2304and an inner wall 2306 and a radially spaced apart outer wall 2308. Theblade 2300 is centered about and rotates about its central axis ofrotation R. In one exemplary embodiment, the rotary knife blade 2300 isa straight style rotary knife blade in which the cutting angle CA of theblade section 2360 with respect to the blade cutting plane CP defined bythe blade cutting edge 2361 is less than 90°. The cutting angle CA ofthe straight blade 2300 is very “steep” and more aggressive than a flatblade or a hook blade, such as the rotary knife blades 300, 1300. Astraight blade is particularly useful when make deep or plunge cuts intoa product, i.e., making a deep cut into a meat product for the purposeof removing connective tissue/gristle adjacent a bone. However, theblade—blade housing bearing structure 2550 of the present disclosure andthe other features, characteristics and attributes, as described, of thepower operated rotary knife 2000 may be used with a variety of rotaryknife blades styles, configurations, and sizes and corresponding bladehousings.

The body 2310 of the annular rotary knife blade 2300 includes an upperor first end 2312 and an axially spaced apart lower or second end 2314and an inner wall 2316 and the radially spaced apart outer wall 2318.The blade section 2360 includes an upper end 2362, defined by adiscontinuity or knee 2362 a in an outer wall 2368 of the blade section2360, and a lower end 2364, which is coincident with the blade cuttingedge 2361. The body 2310 of the rotary knife blade 2300 includes adriven gear 2340, substantially similar to the driven gear 340 of theblade body 300 of the first exemplary embodiment and the outer wall 2318of the blade body 2310 includes an arcuate surface 2319, substantiallysimilar to the arcuate surface 319 of the blade body 300 of the firstexemplary embodiment. The arcuate surface 2319 includes both an outersurface 2340 b of the driven gear 2340 and the first bearing surface2322, substantially similar to the outer surface 340 b of the drivengear 340 and the bearing surface 322 of the blade body 310 of the firstexemplary embodiment. The arcuate surface 2319, when viewed in threedimensions, may be viewed as an annular protruding bearing bead 2311,forming a radially protruding portion of the outer wall 2318 of theblade body 2310 and defining the first bearing surface 2322. The outerwall 2318 of the body 2310 includes an upper portion 2318 a, a middleportion 2318 b, and a lower portion 2318 c.

As mentioned above, the bearing region 2320 of the blade body 2310includes both the first bearing surface 2322, defined by the convexarcuate surface 2319, and the second bearing surface 2382, defined bythe concave arcuate surface 2380 a. The second bearing surface 2382 ispart of a central portion 2385 of the bearing race 2380. The centralportion 2385 of the bearing race 2380, which includes both the upper andlower regions 2381 a, 2381 b of the bearing race 2380, defines theconcave arcuate surface 2380 a. The concave arcuate surface 2380 a, inturn, defines the second bearing surface 2382, including the upper andlower hearing faces 2384 a, 2384 b. When viewed in two dimensions, theconcave arcuate surface 2380 is characterized by a constant radius ofcurvature RAD2 and a center point CPT2. In one exemplary embodiment, thearcuate surface 2380 a has a radius of curvature RAD2 of approximately0.035 in. The first bearing surface 2322 is part of the rotary knifeblade bearing region 2320 and is part of the first blade—blade housingbearing structure 2560, while the second bearing surface 2382 is part ofthe rotary knife blade bearing region 2320 and is part of the secondblade—blade housing bearing structure 2570 of the combined blade—bladehousing bearing structure 2550.

The upper portion 2318 a of the outer wall 2318 of the rotary knifeblade body 2310 includes the convex arcuate surface 2319, substantiallysimilar to the arcuate surface 319 of the outer wall 318 of the rotaryknife body 310 of the first exemplary embodiment, which comprises boththe outer surface 2340 b of the driven gear 2340 and the bearing surface2322. The arcuate surface 2319 is characterized as being a constantradius of curvature RAD and a center point CPT. The bearing surface 2322includes an upper bearing face 2324 a disposed above a midpoint locationor radial outermost location 2319 k of a second intermediate portion2319 d of the arcuate surface 2319 and a lower bearing face 2324 bdisposed below the midpoint location or radial outermost location 2319 kof the second intermediate portion 2319 d.

The middle portion 2318 b of the outer wall 2318 of the rotary bladebody 2310 includes the radially inwardly extending or concave bearingrace 2380. The bearing race 2380 includes the central or middle portion2385 that defines the concave arcuate surface 2380 a. As mentionedpreviously, the concave arcuate surface 2380 a defines the secondbearing surface 2382. The second bearing surface 2382 includes the upperbearing face 2384 a disposed above a midpoint or radially innermostlocation 2380 c of the arcuate surface 2380 a and the lower bearing face2384 b disposed below the midpoint 2380 c. The midpoint 2380 c of thearcuate surface 2380 a corresponds to and is coincident with theradially innermost midpoint location 2381 k of the bearing race 2380.Viewed in three dimensions, it should be understood that the midpointlocations 2380 c, 2381 k form a circle centered about the blade centralaxis of rotation R since the arcuate surface 2380 a of the bearing race2380 forms a portion of an inner surface of an annular ring having acircular cross section (bull's nose ring). Reference is made to thediscussion of the annular ring 319 f of the convex arcuate surface 319of the rotary knife blade 300 of the first exemplary embodiment. Thedifference here being that the arcuate surface 2380 a of the bearingrace 2380, being concave, would correspond to a portion of an innersurface of the annular ring, as opposed to a portion of the outersurface of the annular ring 319 f corresponding to the convex arcuatesurface 319 of the rotary knife blade 300.

As can best be seen in FIG. 29, a horizontal radius or straight line RD2extending orthogonally from the blade central axis of rotation R passingthrough the midpoint location 2380 c of the arcuate surface 2380 a andthe midpoint location 2381 k of the intermediate portion 2381 d of thebearing race 2380 would also pass through the center point CPT2 of thearcuate surface 2380 a. The radius line RD2 is parallel to therotational plane RP of the blade 2300. Extending between the centralportion 2385 of the bearing race 2380 and the lower end 2319 e of thearcuate surface 2319 is an upper transition portion 2386. Extendingbetween the central portion 2385 of the bearing race and an upper end ofthe lower portion 2318 c is a lower transition portion 2388. The secondbearing surface 2382 is part of the rotary knife blade bearing region2320 and the second blade—blade housing bearing structure 2570. Thelower portion 2318 c of the outer wall 2318 includes the verticalsection 2318 d that terminates at the lower end 2314 of the body 2310and defines the discontinuity or knee 2362 a that defines the upper end2362 of the blade section 2360.

Blade Housing 2400

The blade housing 2400 (FIGS. 30 and 30A) includes a mounting section2402 substantially similar in function and structure to the mountingsection 402 of the blade housing 402 of the first exemplary embodiment.The blade housing 2400 also includes the blade support section 2450 thatsupports the rotary knife blade 2300 for rotation about its central axisof rotation R and includes the inner wall 2452 and a radially spacedapart outer wall 2454 and an upper end 2456 and an axially spaced apartlower end 2458. Turning to the inner wall 2352 of the blade supportsection 2450, the inner wall 2352 includes a generally vertical upperportion 2352 a, adjacent the upper end 2456 of the blade housing bladesupport section 2450, the middle portion 2352 b, and a lower portion2352 c, adjacent the lower end 2458 of the blade housing blade supportsection 2450. The middle portion 2452 b of the inner wall 2352 includesa bearing race 2466, substantially similar to the bearing race 466 ofthe blade support section 450 of the blade housing 400 of the firstexemplary embodiment. The bearing race 2466 includes an arcuate surface2466 a formed on a back wall 2469 of the bearing race 2466. The arcuatesurface 2466 a of the bearing race 2466, when viewed in two dimensions,is characterized by a constant radius of curvature BRRAD and a centerpoint BRCPT. The arcuate surface 2466 a comprises the first concavearcuate bearing surface 2462 which includes an upper arcuate bearingface 2464 a disposed above an intermediate portion 2466 a of the arcuatesurface 2466 a of the bearing race 2466 and a lower arcuate bearing face2464 b disposed below the intermediate portion 2466 c, substantiallysimilar to the concave first bearing surface 1462 and the upper andlower bearing faces 1464 a, 1464 b of the arcuate surface 1466 a of theback wall 1469 of the bearing race 1466 of the blade housing bladesupport section 1450 of the second exemplary embodiment. Theintermediate portion 2466 c includes a vertex location or midpointlocation 2466 k of the bearing race 3466. The midpoint location 2466 k,as can best be seen in FIG. 25, represents a location of the bearingrace 2466 which is radially furthest from the center line CBH of theblade housing 2400. The first bearing surface 2462 is part of the bladehousing bearing region 2460 and the first blade—blade housing bearingstructure 2560. The bearing race 2466 includes an upper generallyhorizontal upper surface 2467 that transitions to the vertical upperportion 2452 a of the inner wall 2452 and a lower curved surface 2468that transitions to the bearing bead 2480.

With regard to the lower portion 2452 c of the inner wall 2352 of theblade support section 2350 of the blade housing 2400, the wall 2352includes the radially protruding bearing bead 2480 which extendsradially in a direction toward the blade housing center line CBH. Thebearing bead 2480 includes, in the central portion 2485, the convexarcuate surface 2480 a. Viewed radially with respect to the bladehousing center line CBH, the convex arcuate surface 2480 a is positionedradially intermediate a vertical extent 2452 d of the upper portion 2452a of the inner wall 2452 (radially closest to the center line CBH) andthe concave arcuate surface 2466 a of the bearing race 2466 (radiallymore distant from the center line CBH) of the blade housing bladesupport section 2450. The convex arcuate surface 2480 a is characterizedby a constant radius of curvature BBRAD and center point BBCPT anddefines the convex second bearing surface 2482 of the blade housingbearing region 2460. The second bearing surface 2482 includes an upperbearing face 2484 a disposed above an intermediate portion 2480 c of theconvex arcuate surface 2480 a and a lower bearing face 2484 b disposedbelow the intermediate portion 2480 c. The intermediate portion 2480 cincludes a vertex location or midpoint location 2480 k representing theradially innermost location (closest to the blade housing center lineCBH) of the bearing bead 2480. The center point BBCPT of the radius ofcurvature BBRAD of the arcuate surface 2480 a is radially aligned alonga horizontally extending straight or radius line RL2 (FIG. 30A)extending orthogonally from the blade housing central line CBH to themidpoint location 2480 k of the intermediate portion 2480 c. The upperbearing face 2384 a of the second bearing surface 2382 of the bearingrace 2380 of the rotary knife blade body 2310 bears against the upperbearing face 2484 a of the second bearing surface 2482 of the bearingbead 2480 of the blade housing blade support section 2450, while thelower bearing face 2384 b of the second bearing surface 2382 of thebearing race 2380 of the rotary knife blade body 2310 bears against thelower bearing face 2484 b of the second bearing surface 2482 of thebearing bead 2480 of the blade housing blade support section 2450. Thesecond bearing surface 2482 of the bearing bead 2480 is part of theblade housing bearing region 2460 and is part of the second blade—bladehousing bearing structure 2570.

In one exemplary embodiment, the radius of curvature BBRAD of the convexarcuate surface 2480 a is approximately 0.030 in. Advantageously, toavoid binding between the blade bearing region 2320 and the bladehousing bearing region 2460, the radius of curvature BBRAD of the convexsecond bearing surface 2482 of the arcuate convex surface 2480 a of thebearing bead 2480 of the blade housing 2400 is slightly smaller inmagnitude than the mating radius of curvature RAD2 of the concavearcuate surface 2380 a of the rotary knife blade bearing race 2380 (inone exemplary embodiment of the assembled combination 2500, therespective values are 0.030 in. v. 0.035 in.). Similarly, to avoidbinding the radius of curvature RAD of the convex first bearing surface2322 of the arcuate convex surface 2319 of the rotary knife blade 2300is slightly smaller in magnitude than the radius of curvature BRRAD ofthe concave first bearing surface 2462 of the concave arcuate surface2466 a of the bearing race 2466 of the blade housing 2400 (in oneexemplary embodiment of the assembled combination 2500, the respectivevalues are 0.047 in. v. 0.052 in., as discussed with respect to thesecond exemplary embodiment of the power operated rotary knife 1000).Disposed above the central portion 2484 of the bearing bead 2480 is atransition portion 2486 of the bead 2480 that transitions between thecentral portion 2484 and the lower surface 2468 of the bearing race2466. The second bearing surface 2482 is part of the blade housingbearing region 2460 and the first blade—blade housing bearing structure2560.

In one exemplary embodiment of the blade housing 2400, the bearing bead2380 is discontinuous or interrupted circumferentially, that is, thebead 2480 is interrupted about its circumference by circumferentialinterrupted regions or sections 2490 where the bead does not protruderadially inwardly toward the blade housing central axis CBH. In thoseinterrupted regions 2490 of the bead 2480, the bearing bead does notpresent a bearing surface 2482 to bear against the mating bearingsurface 2382 of the rotary knife blade 2300. Portions of two suchinterrupted regions or sections 2490 of the bearing bead 2480 can beseen in the section view of the blade housing 2400 schematicallydepicted in FIG. 30. As can be seen in FIG. 30, raised or protrudingregions or sections 2492 of the bead 2480, which include the bearingsurface 2482 extend circumferentially from the region of the bladehousing split 2401 a. In one exemplary embodiment, there are a total offive interrupted regions 2490 of the bearing bead 2380 spacedcircumferentially about the bearing bead 2480. Extending between eachpair of the five interrupted regions 2490 are six protruding regions2492. In one exemplary embodiment of the blade housing 2400, four of theinterrupted regions 2490 subtend or have an arcuate extent with respectto the blade housing center line CBH in a range of 13-18° and oneinterrupted region, positioned diametrically opposite from the bladehousing split 2401 subtends or has an arcuate extent in a range of29-34°.

The blade—blade housing structure 2500 of the present disclosure and theother features, characteristics and attributes, as described above, ofthe power operated rotary knife 100 may be used with a variety of rotaryknife blades styles, configurations, and sizes and corresponding bladehousings. The exemplary rotary knife blade 2300 is a straight bladestyle rotary knife blade. Numerous other blade styles, including, butnot limited to, flat and hook style blades and combinations of bladestyles may be utilized, with an appropriate blade housing, in the poweroperated rotary knife 2000 of the present disclosure, as would beunderstood by erne of skill in the art. It is the intent of the presentdisclosure to cover all such rotary knife blade styles and sizes,together with the corresponding blade housings, that may be used in thepower operated rotary knife 200.

Fourth Embodiment—Power Operated Rotary Knife 3000

A fourth exemplary embodiment of a power operated rotary knife of thepresent disclosure is shown generally at 3000 in FIGS. 31-35. The poweroperated rotary knife 3000 includes an elongated handle assembly 3110, ahead assembly 3200, which is releasably secured to a front or distal endof the handle assembly 3110, and a drive mechanism 3600, including agear train 1604. The power operated rotary knife 3000 extends between adistal or forward end 3001 and a proximal or rearward end 3002 of theknife 3000. The head assembly 3200 includes a frame body 3250 andclamping assembly 3220 which secures an assembled blade—blade housingcombination 3500 to the frame body 3250. The assembled blade—bladehousing combination 3500 includes an annular rotary knife blade 3300 andan annular blade housing 3400 supporting the rotary knife blade 3300 forrotation about the knife blade's central axis of rotation R.

The handle assembly 3110 is substantially similar to the handle assembly110 of the power operated rotary knife 100 of the first exemplaryembodiment. The handle assembly 3110 extends along a longitudinal axisLA and includes a handle assembly throughbore 3115. The longitudinalaxis LA of the handle assembly 3110 extends through a center of theelongated throughbore 3115 and is orthogonal to and intersects therotary knife blade central axis of rotation R. The drive mechanism 3600and gear train 3604 are substantially similar to the drive mechanism 600and gear train 604 of the power operated rotary knife 100 of the firstexemplary embodiment. The frame body 3250 and the clamping assembly 3220of the head assembly 3200 are substantially similar to the frame body250 and the clamping assembly 220 of the head assembly 200 of the poweroperated rotary knife 100 of the first exemplary embodiment. Theassembled blade—blade housing combination 3500 the power operated rotaryknife 3000 includes the annular blade housing 3400. The annular bladehousing 3400 of the fourth exemplary embodiment is substantially similarto the annular blade housing 2400 of the power operated rotary knife2000 of the third exemplary embodiment.

Various components and assemblies of the power operated rotary knife3000 are substantially similar in structure and/or function tocorresponding components and assemblies of the power operated rotaryknife 100 and/or the power operated rotary knife 1000 and/or the poweroperated rotary knife 2000, as previously described. In the interest ofbrevity, components and assemblies of the power operated rotary knife3000 that are similar to the corresponding components and assemblies ofthe power operated rotary knife 100 of the first exemplary embodimentand/or the power operated rotary knife 1000 of the second, exemplaryembodiment and/or the power operated rotary knife 2000 of the thirdexemplary embodiment in structure and/or function will not be fullydescribed herein. Instead, reference is made to the description of suchcomponents and assemblies set forth above in connection with the poweroperated rotary knife 100 and/or the power operated rotary knife 1000and/or the power operated rotary knife 200, as set forth above.Materials/fabrication of components and assemblies of the power operatedrotary knife 3000 are similar to materials/fabrication of correspondingcomponents and assemblies of the power operated rotary knife 100, asdescribed above. Such descriptions of components and assemblies of thepower operated rotary knife 100 of the first exemplary embodiment and/orthe components and assemblies of the power operated rotary knife 1000 ofthe second exemplary embodiment and/or the components and assemblies ofthe power operated rotary knife 2000 of the third exemplary embodimentare hereby incorporated by reference in the following description of thepower operated rotary knife 3000 of the fourth exemplary embodiment.Identification of axes, lines, planes and directions for the poweroperated rotary knife 3000, as set forth herein, will be the same asused for the description of the power operated rotary knife 100 of thefirst exemplary embodiment and/or the power operated rotary knife 1000of the second exemplary embodiment and/or the power operated rotaryknife 2000 of the third exemplary embodiment.

Like the rotary knife blade 2300 and the annular blade housing 2400 ofthe assembled combination 2500 of the power operated rotary knife 2000of the third exemplary embodiment, the assembled combination 3500 of therotary knife blade 3300 and the annular blade housing 3400 comprises ablade—blade housing bearing structure 3550 that includes a firstblade—blade housing bearing structure 3560 and a second blade—bladehousing bearing structure 3570. In the power operated rotary knife 2000of the third exemplary embodiment, the first blade—blade housing bearingstructure 2560 included the first arcuate bearing surface 2322 of thebearing region 2320 of the rotary knife blade 2300 engaging and bearingagainst the first arcuate bearing surface 2462 of the bearing region2460 of the blade support section 2450 of the annular blade housing2400. The first blade—blade housing bearing structure 3560 of the poweroperated rotary knife 3000 has substantially the same structure, namely,the first blade—blade housing bearing structure 3560 includes a firstarcuate bearing surface 3322 of a bearing region 3320 of the rotaryknife blade 3300 which engages and bears against a first arcuate bearingsurface 3462 of a blade support section 3450 of the annular bladehousing 3400. As discussed below, with respect to the bearing region3360 of the rotary knife blade 3300, the second blade—blade housingbearing structure 3570 is modified with respect to the secondblade—blade housing bearing structure 2570 of the power operated rotaryknife 2000 of the third exemplary embodiment.

Rotary Knife Blade 3300

As can best be seen in FIGS. 33 and 34, the rotary knife blade 3300includes an annular body 3310 and a blade section 3360 extending fromthe body 3310. The blade 3300 includes an upper end or first end 3302and an axially spaced apart lower end or second end 3304, defining acutting edge 3361 of the blade 3300, and an inner wall 3306 and aradially spaced apart outer wall 3308. In one exemplary embodiment, therotary knife blade 3300 is a flat blade style rotary knife blade. Theterm “flat” refers to the profile of the blade section 3360 and, inparticular, to a cutting angle CA (FIG. 33) of the blade section 3360with respect to a cutting plane CP that is congruent with the cuttingedge 3361 of the blade 3300. The angle CA of the blade section 3360 withrespect to the cutting plane CP is relatively large. As can be seen inFIG. 33, the cutting angle CA, that is, the angle between the bladesection 3360 and the cutting plane CP, as measured with respect to theblade section inner wall 3366 is an obtuse angle, greater than 90°. Thislarge, obtuse cutting angle CA is referred to as a “shallow” bladecutting profile. The inner wall 3366 is generally smooth, frustoconicalshape. As a product is being trimmed or cut by the flat blade 3300, thecut material layer moves easily along the inner wall 3366 the flat blade3300. The flat blade 3300 is particularly useful for trimming thickerlayers of material from a product, e.g., trimming a thicker layer of fator meat tissue from a piece of meat, as the power operated rotary knife3000 is moved over the product in a sweeping motion. This is truebecause even thicker layers of cut or trimmed material will flow withminimal drag or friction over the inner wall 3366 of the flat blade3300.

The blade section 3360 of the rotary knife blade 3300 includes an upperend 3362, defined by a discontinuity or knee 3362 a in an outer wall3368 of the blade section 3360, and a lower end 3364, which iscoincident with the blade cutting edge 3361, the cutting plane CP andthe lower end 3304 of the rotary knife blade 3300. The blade section3360 also includes the inner wall 3366 and the radially spaced apartouter wall 3368.

Turning to the annular body 3310 of the rotary knife blade 3300, thebody 3310 is generally similar to the annular body 2310 of the annularrotary knife blade 2300 of the third exemplary embodiment, with theexcept for the configuration of a second bearing surface 3382 of abearing region 3320 of the rotary knife blade 3300. Specifically, in theannular body 2310 of the annular rotary knife blade 2300 of the thirdexemplary embodiment, the second bearing surface 2382 was arcuate, beingdefined by a portion of the concave arcuate surface 2380 a of thecentral portion 2385 of the bearing race 2380 which was part of theouter wall 2318 of the body 2310. By contrast, as can best be seen inFIG. 34, an outer wall 3318 of the annular body 3310 of the annularrotary knife blade 3300 includes a concave generally V-shaped bearingrace 3380.

The bearing race 3380 of the outer wall 3318 of the blade body 3310defines the second arcuate bearing surface 3382 of the bearing region3320 of the rotary knife blade 3300. The second bearing surface 3382 isconcave with respect to the outer wall 3318 of the body 3310 of therotary knife blade 3300 and extends in a direction toward the bladecentral axis of rotation R. The concave bearing race 3380 of the bladebody 3310 extends along the outer wall 3318 of the body 3310 and extendsin a radial direction toward the blade central axis of rotation R in agenerally v-shaped horizontal orientation, that is, the bearing race3380 may be viewed as a v-shaped opening in the outer wall 3318 of thebody, wherein the “v” is tipped to a horizontal orientation with avertex of the “v” closest to the blade central axis of rotation R.Reference to the bearing race 3380 as being “v-shaped” shall beunderstood to mean that the opening in the outer wall 3318 defining thebearing race 3380 is understood to be with the “v” opening in thehorizontal orientation, as best seen in FIG. 34. The concave bearingrace 3380 extends from an upper end portion 3381 c, through anintermediate portion 3381 d and terminates at a lower end portion 3381 eof the bearing race 3380. The intermediate portion 3381 d of the bearingrace 3380 defines a radially innermost midpoint location or intermediatelocation 3381 k of the bearing race 3380 and, in one exemplaryembodiment, defines a radially innermost location of the outer wall 3318of the body 3310. The bearing race 3380 includes an upper region 3381 aextending between the upper end portion 3381 c and the intermediateportion 3381 d and a lower region 3381 b extending between theintermediate portion 3381 d and the lower end portion 3381 e. The secondbearing surface 3382 is generally v-shaped (and horizontally oriented)and includes a linear, angled or frustoconical upper bearing face 3384 ain the upper region 3381 a of the bearing race 3380 disposed above themidpoint location 3381 k and further includes a linear, angled orfrustoconical lower bearing face 3384 b in the arcuate lower region 3381b of the bearing race 3380. The frustoconical upper bearing face 3384 aconverges in a direction proceeding toward the lower end 3314 of theblade body 3314 or the lower end 3304 of the rotary knife blade 3300,that is, in the downward direction DW, while the frustoconical lowerbearing surface 3384 b converges in a direction proceeding toward theupper end 3312 of the blade body 3310 or the upper end 3302 of therotary knife blade 3300, that is, in the upward direction UP. Viewed intwo dimensions the frustoconical upper bearing surface 3384 a can beviewed as a pair of an angled lines at opposite radial sides of therotary knife blade 3300 in the upper region 3381 a of the bearing race3380, the pair of angled lines of the upper bearing surface 3384 aconverging in a direction proceeding in the downward direction DW, whilethe frustoconical lower bearing surface 3384 b can be viewed as a pairof an angled lines at opposite radial sides of the rotary knife blade3300 in the lower region 3381 b of the bearing race 3380, the pair ofangled lines of the lower bearing surface 3384 b converging in adirection proceeding in the upward direction UP.

The frustoconical second hearing surface 3382 of the bearing race 3380is defined by a concave v-shaped arcuate surface 2380 a of the bearingrace 3380 which is part of a concave central portion 3385 of the bearingrace 3380. The bearing race 3380 extends from an upper end portion 3381c though an intermediate portion 3381 d and terminates at a lower endportion 3381 e. The bearing race 3380 includes a central portion 3385which includes a generally concave v-shaped surface 3380 a. The concavev-shaped surface 3380 a defines the v-shaped second bearing surface3382, as opposed to the arcuate second bearing surface 2382 of the mildexemplary embodiment. The second bearing surface 3382 includes theangled or frustoconical upper bearing surface or face 3384 a disposedabove a midpoint or radially innermost location 3380 c of the concavev-shaped surface 3380 a and the angled or frustoconical lower bearingsurface or face 3384 b disposed below the midpoint 3380 c of thev-shaped surface 3380 a, as opposed to the arcuate upper bearing face2384 a and arcuate lower bearing face 2384 b of the second bearingsurface 2382 of the third exemplary embodiment. The midpoint 3380 c ofthe v-shaped surface 3380 a corresponds to and is coincident with theradially innermost midpoint location 3381 k of the bearing race 3380.Viewed in three dimensions, the angled or frustoconical upper bearingface 3384 a of the second bearing surface 3382 defines a frustoconicalsurface 3390 a which may be viewed as a frustum of a right angled conewhich converges a direction proceeding toward the lower end 3304 of theblade 3300, that is, in the downward direction DW, while the angled orfrustoconical lower bearing face 3384 b of the second bearing surface3382 defines a right angled cone frustoconical surface 3390 b convergingin a direction proceeding toward the upper end 3302 of the blade 3000,that is, in the upward direction UP.

The body 3310 of the rotary knife blade 3300 includes a driven gear3340, substantially similar to the driven gear 340 of the blade body 300of the first exemplary embodiment and the outer wall 3318 of the bladebody 3310 includes an arcuate surface 3319, substantially similar to thearcuate surface 319 of the blade body 300 of the first exemplaryembodiment. The arcuate surface 3319 includes both an outer surface 3340b of the driven gear 3340 and the first bearing surface 3322,substantially similar to the outer surface 340 b of the driven gear 340and the bearing surface 322 of the blade body 310 of the first exemplaryembodiment. The arcuate surface 3319, when viewed in three dimensions,may be viewed as an annular protruding bearing bead 3311, forming aradially protruding portion of the outer wall 3318 of the blade body3310 and defining the first bearing surface 3322.

The bearing region 3320 of the blade body 3310 includes both the firstbearing surface 3322, defined by the convex arcuate surface 3319 of thebearing bead 3311, and the second bearing surface 3382, defined by theconcave v-shaped surface 3380 a of the bearing race 3380. The v-shapedsurface 3380 a is part of the central portion 3385 of the bearing race3380. The first bearing surface 3322 is part of the rotary knife Wadebearing region 3320 and is part of the first blade—blade housing bearingstructure 3560, while the second bearing surface 3382 is part of therotary knife blade bearing region 3320 and is part of the secondblade—blade housing bearing structure 3570 of the combined blade—bladehousing bearing structure 3550.

An upper portion 3318 a of the outer wall 3318 of the rotary knife bladebody 3310 includes the convex arcuate surface 3319, substantiallysimilar to the arcuate surface 319 of the outer wall 318 of the rotaryknife body 310 of the first exemplary embodiment, which comprises boththe outer surface 3340 b of the driven gear 3340 and the bearing surface3322. The arcuate surface 3319 is characterized as being a constantradius of curvature RAD and a center point CPT. The bearing surface 3322includes an upper bearing face 3324 a disposed above the midpointlocation or radial outermost location 3319 k of the second intermediateportion 3319 d of the arcuate surface 3319 and a lower bearing lace 3324b disposed below the midpoint location or radial outermost location 3319k of the second intermediate portion 3319 d of the arcuate surface 3319.

A lower portion 3318 b of the outer wall 3318 of the rotary blade body3310 includes the radially inwardly extending or concave bearing race3380. The bearing race 3380 includes the central or middle portion 3385that defines the concave v-shaped surface 3380 a. The concave v-shapedsurface 3380 a defines the second bearing surface 3382. The secondbearing surface 3382 includes the upper bearing face 3384 a disposedabove a midpoint or radially innermost location 3380 c of the arcuatesurface 3380 a and the lower bearing face 3384 b disposed below themidpoint 3380 c. Extending between the central portion 3385 of thebearing race 3380 and the lower end 3319 e of the arcuate surface 3319is an upper transition portion 3386. Extending between the centralportion 3385 of the bearing race and the upper end 3362 of the bladesection 3360 is a lower transition portion 3388. The second bearingsurface 3382 is part of the rotary knife blade bearing region 3320 andthe second blade—blade housing bearing structure 3570.

Blade Housing 3400

The blade housing 3400 (FIG. 35) includes a mounting section 3402substantially similar in function and structure to the mounting section402 of the blade housing 402 of the first exemplary embodiment. As canbest be seen in FIG. 35, the blade housing 3400 also includes the bladesupport section 3450 that supports the rotary knife blade 3300 forrotation about Its central axis of rotation R and includes the innerwall 3452 and a radially spaced apart outer wall 3454 and an upper end3456 and an axially spaced apart lower end 3458. Turning to the innerwall 3352 of the blade support section 3450, the inner wall 3352includes a generally vertical upper portion 3352 a, adjacent the upperend 3456 of the blade housing blade support section 3450, a middleportion 3352 b, and a lower portion 3352 c, adjacent the lower end 3458of the blade housing blade support section 3450. The middle portion 3452b of the inner wall 3352 includes a bearing race 3466, substantiallysimilar to the bearing race 466 of the blade support section 450 of theblade housing 400 of the first exemplary embodiment. The bearing race3466 includes an arcuate surface 3466 a formed on a back wall 3469 ofthe bearing race 3466. The arcuate surface 3466 a of the bearing race3466, when viewed in two dimensions, is characterized by a constantradius of curvature BRRAD and a center point BRCPT. The arcuate surface3466 a comprises the first concave arcuate bearing surface 3462 whichincludes an upper arcuate bearing face 3464 a disposed above anintermediate portion 3466 c of the arcuate surface 3466 a of the bearingrace 3466 and a lower arcuate bearing face 3464 b disposed below theintermediate portion 3466 c, substantially similar to the concave firstbearing surface 1462 and the upper and lower bearing faces 1464 a, 1464b of the arcuate surface 1466 a of the back wall 1469 of the bearingrace 1466 of the blade housing blade support section 1450 of the secondexemplary embodiment. The intermediate portion 3466 c includes a vertexlocation or midpoint location 3466 k of the bearing race 3466. Themidpoint location 3466 k, as can best be seen in FIG. 35, represents alocation of the bearing race 3466 which is radially furthest from thecenter line CBH of the blade housing 3400. The bearing race 3466includes an upper generally horizontal upper surface 3467 thattransitions to an angled upper portion 3452 a of the inner wall 3452 anda lower curved surface 3468 that transitions to a bearing bead 3480,which is part of the lower portion 3352 c of the inner wall 3352 of theblade housing bearing support section 33450. The first bearing surface3462, including the upper and lower 3464 a, 3464 b bearing faces, ispart of the blade housing bearing region 3460 and the first blade—bladehousing bearing structure 3560.

With regard to the lower portion 3452 c of the inner wall 3352 of theblade support section 3350 of the blade housing 3400, the inner wall3352 includes the radially protruding bearing bead 3480 which extendsradially in a direction toward the blade housing center line CBH. Thebearing bead 3480 includes, in a central portion 3485 of the bead 3480,a convex arcuate surface 3480 a. Viewed radially with respect to theblade housing center line CBH, the convex arcuate surface 3380 a ispositioned radially closer to the center line CBH than the concavearcuate surface 3466 a of the bearing race 3466, which is radially moredistant from the center line CBH of the blade housing blade supportsection 3450. The convex arcuate surface 3480 a is characterized by aconstant radius of curvature BBRAD and center point BBCPT and definesthe convex second bearing surface 3482 of the blade housing bearingregion 3460. The second bearing surface 3482 includes an upper bearingface 3484 a disposed above an intermediate portion 3480 c of the arcuatesurface 3480 a and a lower bearing face 3484 b disposed below theintermediate portion 3480 c. The intermediate portion 3480 c includes avertex location or midpoint location 3480 k representing the radiallyinnermost location (closest to the blade housing center line CBH) of thebearing bead 3480.

In the assembled blade—blade housing combination 3500, the arcuate upperbearing face 3324 a of the first bearing surface 3322 of the bearingbead 3311 of the body 3310 of the rotary knife blade 3300 bears againstthe arcuate upper bearing face 3464 a of the first bearing surface 3462of the bearing race 3466 of the blade housing blade support section3450, while the arcuate lower bearing face 3324 b of the first bearingsurface 3322 of the bearing bead 3311 of the body 3310 of the rotaryknife blade 3300 bears against the arcuate lower bearing face 3464 b ofthe first bearing surface 3462 of the beating race 3466 of the bladehousing blade support section 3450. The first bearing surface 3322 ofthe bearing bead 3311 of the rotary knife body 3310 is part of therotary knife blade bearing region 3320 and is part of the firstblade—blade housing bearing structure 3560. The first bearing surface3462 of the bearing race 3466 of the blade housing blade support sectionis part of the blade housing bearing region 3460 and is part of thefirst blade—blade housing bearing structure 3560.

In the assembled blade—blade housing combination 3500, the angled orfrustoconical upper bearing face 3384 a of the second bearing surface3382 of the bearing race 3380 of the rotary knife blade body 3310 bearsagainst the upper bearing face 3484 a of the second bearing surface 3482of the bearing bead 3480 of the blade housing blade support section3450, while the angled or frustoconical lower bearing face 3384 b of thesecond bearing surface 3382 of the bearing race 3380 of the rotary knifeblade body 3310 bears against the lower bearing face 3484 b of thesecond bearing surface 3482 of the bearing bead 3480 of the bladehousing blade support section 3450. The second bearing surface 3382 ofthe bearing race 3380 of the rotary knife body 3310 is part of therotary knife blade bearing region 3320 and is part of the secondblade—blade housing bearing structure 3570. The second bearing surface3482 of the bearing bead 3480 of the blade housing support section 3450is part of the blade housing bearing region 3460 and is part of thesecond blade—blade housing bearing structure 3570.

The blade—blade housing structure 3500 of the present disclosure and theother features, characteristics and attributes, as described above, ofthe power operated rotary knife 3000 may be used with a variety ofrotary knife blades styles, configurations, and sizes and correspondingblade housings. As mentioned above, the exemplary rotary knife blade3300 is a flat blade style rotary knife blade. Numerous other bladestyles, including, but not limited to, hook and straight style bladesand combinations of blade styles may be utilized, with an appropriateblade housing, in the power operated rotary knife 3000 of the presentdisclosure, as would be understood by one of skill in the art. It is theintent of the present disclosure to cover all such rotary knife bladestyles and sizes, together with the corresponding blade housings, thatmay be used in the power operated rotary knife 3000.

Fifth Embodiment—Blade—Blade Housing Combination 4500

An alternate exemplary embodiment of an assembled combination of arotary knife blade—annular blade housing is schematically depictedgenerally at 4500 in FIGS. 36, 36A and 37. The assembled combination4500 includes an annular rotary knife blade 4300 and an annular bladehousing 4400. The annular rotary knife blade 4300 (FIGS. 36 and 36A) issubstantially similar in structure and function to the annular rotaryknife blade 1300 of the power operated rotary knife 1000 of the secondexemplary embodiment. In the interests of brevity, reference is made tothe prior description of the rotary knife blade 1300 of the secondexemplary embodiment and associated drawing Figures, and suchdescription and drawings of the rotary knife blade 1300 of the secondexemplary embodiment are hereby incorporated herein by reference.

Blade Housing 4400

The annular blade housing 4400 is generally similar in structure andfunction to the annular blade housing 1400 of the power operated rotaryknife 1000 of the second exemplary embodiment, except for theconfiguration of a bearing region 4460 of a blade support section 4450of the annular blade housing 4400. Specifically, a configuration of abearing race 4466 of the bearing region 4460 of the blade supportsection 4450 of the blade housing 4400 is different than theconfiguration of the bearing race 1466 of the bearing region 1460 of theblade support section 1450 of the blade housing 1400 in that the bearingrace 4466 includes a radial discontinuity or a concave radial recess4480 in a back wall 4469 of the bearing race 4466, that is, a radialdiscontinuity in a concave, arcuate surface 4466 a formed by the backwall 4469 of the bearing race 4466. The radial recess 4480 is within anintermediate portion 4466 c of the arcuate surface 4466 a of the bearingrace 4466. In the interests of brevity, reference is made to the priordescription of the annular blade housing 1400 the second exemplaryembodiment and associated drawing Figures, and such description anddrawings of the blade housing 1400 of the second exemplary embodimentare hereby incorporated herein by reference. Only the differencesbetween the respective bearing regions 4460, 1460 of the blade housing4400, 1400 will be discussed in detail below.

The generally concave bearing race 4466 includes a generally horizontalsurface 4467 and an axially spaced apart generally horizontal surface4468. Bridging the upper and lower surfaces 4467, 4468 of the hearingrace 4466 is the back wall portion or surface 4469 of the bearing race4466. The back wall portion 4469 includes the concave, generally arcuatesurface 4466 a. The concave, arcuate surface 4466 a of the back wallportion 4469 of the blade housing bearing race 4466, when viewed inthree dimensions, includes an upper arcuate or curved surface 4466 d,extending above the intermediate portion 4466 c of the bearing race4466, and a lower arcuate or curved surface 4466 c of the arcuatesurface 4466 a, extending below the intermediate portion 4466 c of thearcuate surface 4466 a. As noted previously, the intermediate portion4466 c includes the radial discontinuity or radial recess 4480 of thearcuate surface 4466 a. The radial recess 4480, when viewed in threedimensions, defines an annulus 4480 a that is centered about the bladehousing center line CBH. The radial recess 4480 includes an uppertransition surface 4482 and an axially spaced apart lower transitionsurface 4484 spaced apart by an arcuate central or bridging surface4486. The upper and lower transition surfaces 4482, 4484 transitionbetween a general extent of the arcuate surface 4466 a of the bearingrace 4466 and the arcuate central or bridging surface 4486 and eachincludes an inflection point due to the fact that a radius of curvatureof the bridging surface 4486 is different than a radius of curvatureBRRAD of the arcuate surface 4466 a. The central or bridging surface4486 includes a midpoint location 4486 a (FIG. 37) that is radiallyfurthest away from the blade housing central axis or center line CBH.The radial recess 4480 may be viewed an interruption or discontinuity ofthe arcuate surface 4466 a in a direction that is radially away from theblade housing center line CBH. The upper curved surface 4466 d convergesin a direction proceeding toward an upper end 4456 of the blade housingblade support section 4450, while the lower curved surface 4466 econverges in a direction proceeding toward a lower end 4458 of the bladehousing blade support section 4450. That is, the upper and lower curvedsurfaces 4466 d, 4466 e of the back wall surface 4469 have arcuate orcurved side wall which are axially spaced by the radial recess 4480 or,viewed in three dimensions, by the annulus 4480 a.

The arcuate surface 4466 a of the back wall 4469 of the bearing race4466 defines an arcuate bearing surface 4462 comprising an upper arcuatebearing face 4464 a, extending above the intermediate portion 4466 c,and a lower arcuate bearing face 4464 b, extending below theintermediate portion 4466 c. The upper arcuate bearing face 4464 asubstantially corresponds to the upper curved surface 4466 d and thelower arcuate bearing face 4464 b corresponds to the lower curvedsurface 4466 e. The upper and lower bearing faces 1464 a, 1464 b areaxially spaced by the radial recess 4480 of the intermediate portion4466 c of the arcuate surface 4466 a of the back wall 4469 of thebearing race 4466. In one exemplary embodiment, the upper and lowerbearing faces 1464 a, 1464 b, if extended, would intersect within theradial recess 4480 of the intermediate portion 4466 c, approximately atthe midpoint location 4486 a. Except for the discontinuity of thearcuate surface 4466 a resulting from the intermediate portion radialrecess 4480, the arcuate surface 4466 a of the bearing race 4466 ischaracterized by the constant radius of curvature BRRAD and a centerpoint BRCPT. That is, except for the radial recess 4480, the arcuatesurface 4466 a of the bearing race 4466 is continuous, arcuate surface.Since the bearing race 4466 is annular, when viewed in three dimensions,the midpoint location 4486 a of the radial recess 4480 defines acircular line. When viewed in longitudinal section in two dimensions,the upper bearing face 4464 a and lower bearing face 4464 b definearcuate upper and lower arcuate bearing lines 4465 a, 4465 b. Ifextended, the upper and lower arcuate bearing lines would intersect at amidpoint location 4466 k of the arcuate surface 4466 a. The midpointlocation 4466 k of the arcuate surface 4466 a is within the intermediateportion 4466 c of the arcuate surface 4466 a of the bearing race 4466and, when viewed in three dimensions, forms a circle that is centeredabout the blade housing center line CBH. When viewed in two dimensions,the center point BRCPT of the radius of curvature BRRAD of the arcuatesurface 4466 a is radially aligned along a horizontally extending radiusor straight line RL1 (FIG. 37) extending orthogonally from the bladehousing center line CBH passing through the midpoint location 4486 a ofthe central or bridging surface 4486 of the radial recess 4480 and alsopassing through the midpoint location 4466 k of the arcuate surface 4466a of the bearing race 4466. That is, the midpoint location 4486 a of theradial recess 4480 and the midpoint location 4466 k of the arcuatesurface 4466 a of the bearing race 4466 are radially aligned along theradius line RL1. If the blade axis of rotation R and the blade housingcenter line CBH are aligned, the radius line RL1 would be substantiallycoincident with the blade rotational plane RP.

To avoid binding between the blade bearing region 4320 and the bladehousing bearing region 4460, advantageously, the radius of curvatureBRRAD of the arcuate surface 4466 a of the back wall 4469 of the bladehousing bearing race 4466 is greater than the corresponding radius ofcurvature of an arcuate surface of an outer wall of the rotary knifeblade body. In one exemplary embodiment, the radius of curvature BRRADof the arcuate surface 4466 a of the back wall 4469 of the bearing nice4466 of the blade housing blade support section 4450 is 0.052 in., whilethe radius of curvature of the arcuate surface of the outer wall of therotary knife blade body is 0.047 in., approximately 0.005 in. smallerradius. Advantageously, the close matching of the arcuate bearingsurfaces 4322, 4462 of the rotary knife blade 4300 and the blade housing4400 provide a greater potential bearing contact area which, undercertain conditions, may result in a reduced wear rate for the respectivebearing surfaces 4322, 4462. Advantageously, a reduction in wear rate ofthe bearing region 4320 of the rotary knife blade 4300 and/or areduction in wear rate of the bearing region 4460 of the blade supportsection 4450 of the blade housing tends to increase working timeintervals between operator adjustments to a blade housing diameter BHDof the blade support section 4450 of the blade housing 4400 to accountfor looseness of the rotary knife blade 4300 as it rotates within theblade support section 4450 of the blade housing 4400. Increasing workingtime intervals between operator adjustments to the blade housingdiameter BHD increases operator productivity and decreases downtime.

The addition of the radial recess 4480 of the intermediate portion 4466c of the arcuate surface 4466 a of the back wall 4469 of bus bearingrace 4466 advantageously functions as a reservoir for lubrication (foodgrease) from a lubrication assembly (similar to the lubrication assembly230 of the power operated rotary knife 100, as previously described).The lubrication is retained in the radial recess 4480 and, by virtue ofthe operating clearance between the rotary knife blade 1300 and theannular blade housing 4400, coupled with the fact that the rotary knifeblade 1300 is rotating with respect to the blade housing 4400, thelubrication from the radial recess 4480 is distributed or flows into theblade bearing region 4320 and the blade housing bearing region 4460 toprovide for lubrication in the bearing regions 4320, 4460. Under certainoperating and load conditions, provision of the lubrication in thebearing regions 4320, 4460 via the radial recess 4480 willadvantageously tend to reduce the wear of the respective mating bearingfaces 4324 a, 4324 b, 4464 a, 4464 b of the rotary knife blade 4300 andannular blade housing 4400. Furthermore, as explained previously,running clearance between the rotating knife blade 4300 and thestationary blade housing 4400 is necessary to allow the blade 4300 tospin relatively freely with the blade housing 4400. The annular bladehousing 4400 is a split ring 4401 to allow for operator adjustment ofthe blade housing diameter such that proper running clearance betweenthe rotary knife blade 4300 and the blade housing 4400 may be maintainedas the mating bearing laces 4324 a, 4324 b, 4466 a, 4464 b wear duringoperation of the power operated rotary knife 1000. If an operatorreduces the blade housing diameter too much, that is, tightens the bladehousing 4400 such that there is insufficient running clearance, amidpoint location of the rotary knife blade arcuate surface (such as themidpoint location 319 k of the rotary knife blade 300) may be forcedinto contact with a vertex or midpoint location of the blade housingbearing race (such as the vertex location or midpoint location 1466 k ofthe arcuate surface 1466 a of the blade housing bearing race 1466) whichis not desirable. Advantageously, by providing the radial recess 4480 inthe intermediate portion 4466 c of the arcuate surface 4466 a of thebearing race 4466, such undesired contact between the respective bladeand blade housing midpoint locations is precluded or mitigated.

In one exemplary embodiment of the present disclosure, the blade housing4400 is an annular split ring, including the mounting section and theblade support section 4450. The blade support section 4450 extendsaround the entire 360 degrees (360°) circumference of the blade housing4400, except for a circumferential discontinuity resulting from theblade housing split. The mounting section is substantially similar tothe mounting section 1402 of the annular blade housing 1400 of thesecond exemplary embodiment. The blade support section 4450, whichincludes radially spaced apart inner and outer walls 4452, 4454 andaxially spaced apart upper and lower ends 4456, 4458, is centered aboutthe central axis or center line CBH. In the assembled combination 4500of the rotary knife blade 4300 and the blade housing 4400, the bladehousing center line CBH is substantially coincident with the rotaryknife blade central axis of rotation R. As explained previously withregard to the first exemplary embodiment, due to the operating clearancebetween the rotary knife blade 4300 and the blade housing 4400 and thedue to load forces F1 applied to the rotary knife blade 4300, the bladeaxis of rotation R may be slightly angled or tilted with respect theblade central axis CBH. However, under non-loaded conditions, inassembled combination, the rotary knife blade 4300 and the blade supportsection 4450 of the blade housing 4400 are substantially concentric withthe rotary knife blade central axis of rotation R.

Sixth Embodiment—Blade—Blade Housing Combination 5500

An alternate exemplary embodiment of an assembled combination of arotary knife blade—annular blade housing is schematically depictedgenerally at 5500 in FIGS. 38, 38A and 39. The assembled combination5500 includes an annular rotary knife blade 5300 and an annular bladehousing 5400. The annular rotary knife blade 5300 is generally similarin structure and function to the annular rotary knife blade 2300 of thepower operated rotary knife 2000 of the third exemplary embodimentexcept for a configuration of a bearing region 5320 of an outer wall5318 of a body 5310 of the rotary knife blade 5300. The annular bladehousing 5400 is generally similar in structure and function to theannular blade housing 2400 of the power operated rotary knife 2000 ofthe third exemplary embodiment, except for the configuration of abearing region 5460 of a blade support section 5450 of the annular bladehousing 5400. In the interests of brevity, reference is made to theprior description of the annular rotary knife blade 2300 and the annularblade housing 3400 the third exemplary embodiment and associated drawingFigures and which are hereby incorporated herein by reference. Only thedifferences between the respective bearing regions 5320, 5460 withrespect to the respective bearing regions 2320, 2460 of the rotary knifeblade and blade housing 2300, 2400 of the third exemplary embodimentwill be discussed in detail below.

Rotary Knife Blade 5300

A configuration of a bearing race 5380 (FIGS. 38A and 39) of the bearingregion 5320 of the outer wall 5318 of the body 5310 of the rotary knifeblade 5300 is different than the configuration of the bearing race 2380of the bearing region 5320 of the outer wall 2318 of the body 2310 ofthe rotary knife blade 2300 in that the bearing race 5380 includes aradial discontinuity or a concave radial recess 5390 in a concavecentral portion 5385 of the bearing race 5380, that is, a radialdiscontinuity in a concave, arcuate surface 5380 a formed by the concavecentral portion 5385 of the bearing race 5380. The radial recess 5390 iswithin an intermediate portion 5381 d of the arcuate surface 5380 a ofthe bearing race 4466.

The bearing region 5320 of the blade body 5310 includes both a firstbearing surface 5322, defined by the convex arcuate surface 5319, and asecond bearing surface 5382, defined by the concave arcuate surface 5380a. The second bearing surface 5382 is part of the central portion 5385of the bearing race 5380. The central portion 5385 of the bearing race5380, which includes both upper and lower regions 5381 a, 5381 b of thebearing race 5380, defines the concave arcuate surface 5380 a. Theconcave arcuate surface 5380 a, in turn, defines the second bearingsurface 5382. The bearing surface 5382 includes an upper bearing face5384 a disposed above the intermediate portion 5381 d and a lowerbearing face 5384 b disposed below the intermediate portion 5381 d.Except for the discontinuity of the concave arcuate surface 5380 aresulting from the presence of the radial recess 5390 in theintermediate portion 5381 d, when viewed in two dimensions, the concavearcuate surface 5380 a is characterized by a constant radius ofcurvature RAD2 and a center point CPT2. In one exemplary embodiment, thearcuate surface 5380 a has a radius of curvature RAD2 of approximately0.035 in. The first bearing surface 5322 is part of the rotary knifeblade bearing region 5320 and is part of a first blade—blade housingbearing structure 5560, while the second bearing surface 5382 is part ofthe rotary knife blade bearing region 5320 and is part of a secondblade—blade housing bearing structure 5570 of the combined blade—bladehousing bearing structure 5550.

The generally concave bearing race 5380 includes upper and lowertransition portions 5386, 5388 of the bearing race 5380 and the centralportion 5385 of the bearing race 5380 which includes the concave,generally arcuate surface 5380 a. The concave, arcuate surface 5380 a ofthe central portion 5385 of the blade housing bearing race 5380, whenviewed in three dimensions, extends between an upper end portion 5381 cof the bearing race 5380 and a lower end portion 5381 e. The upperregion 5381 a of the arcuate surface 5380 a extends between the upperend portion 5381 c and the intermediate portion 5381 d and the lowerregion 5381 b of the arcuate surface 5380 a extends between theintermediate portion 5381 d and the lower end portion 5381 e. As notedpreviously, the intermediate portion 5381 d includes the radialdiscontinuity or radial recess 5390 of the arcuate surface 5380 a. Theradial recess 5390, when viewed in three dimensions, defines an annulus5390 a that is centered about the blade central axis of rotation R. Theradial recess 5390 includes an upper transition surface 5392 and anaxially spaced apart lower transition surface 5394 spaced apart by aconcave arcuate central or bridging surface 5396. The upper and lowertransition surfaces 5392, 5394 transition between a general extent ofthe arcuate surface 5380 a of the bearing race 5380 and the arcuatecentral or bridging surface 5396. Both the upper and lower transitionsurfaces 5392, 5394 Include an inflection point due to the fact that aradius of curvature of the bridging surface 5396 is different than aradius of curvature RAD2 of the arcuate surface 5380 a. The central orbridging surface 5396 includes a midpoint location 5396 a that isradially closest to the blade central axis of rotation R. The radialrecess 5390 may be viewed an interruption or discontinuity of thearcuate surface 5380 a in a direction that is radially extending towardthe blade central axis of rotation R. The upper bearing face 5384 a,when viewed in three dimensions, converges in a direction proceedingtoward a lower end 5314 of the blade body 5310, while the lower bearingface 5384 b, when viewed in three dimensions, converges in a directionproceeding toward an upper end 5312 of the blade body 5310. That is, theupper and lower bearing faces 5384 a, 5384 b have arcuate or curved sidewalls which fire axially spaced by the radial recess 5390 or, viewed inthree dimensions, by the annulus 5390 a.

In one exemplary embodiment, the upper and lower bearing faces 5384 a,5384 b, if extended, would intersect at a midpoint location 5380 k ofthe arcuate surface 5380 a. The midpoint location 5380 k of the arcuatesurface 5380 a is within the intermediate portion 5381 d of the arcuatesurface 5380 a of the bearing race 5380 and, when viewed in threedimensions, forms a circle that is centered about the blade central axisof rotation R. The center point CPT2 of the radius of curvature RAD2 ofthe arcuate surface 5380 a is radially aligned along a horizontallyextending straight line or radius line RD2 (FIG. 39) extendingorthogonally from the blade central axis of rotation R passing throughthe midpoint location 5396 a of the central or bridging surface 5396 ofthe radial recess 5390 and also passing through the midpoint location5380 k of the arcuate surface 5380 a of the bearing race 5380. That is,the midpoint location 5396 a of the radial recess 5390 and the midpointlocation 5380 k of the arcuate surface 5380 a are radially aligned alongthe radius line RD2. As noted above, except for the discontinuity of thearcuate surface 5380 a resulting from the intermediate portion radialrecess 5390, the arcuate surface 5380 a of the bearing race 5380 ischaracterized by the constant radius of curvature RAD2 and the centerpoint CPT2. That is, except for the radial recess 5390, the arcuatesurface 5380 a of the bearing race 5380 is continuous, arcuate surface.

The advantages of the radial recess 5390 of the arcuate surface 5380 aof the bearing race 5380 are similar to the advantages of the radialrecess 4480 of the concave arcuate surface 4466 a of the bearing race4666 of the blade support section 4450 of the blade housing 3400, asrecited above, and will not be repeated here but instead are herebyincorporated by reference.

Blade Housing 5400

As noted above, the annular blade housing 5400 (FIG. 38A) is generallysimilar in structure and function to the annular blade housing 2400 ofthe power operated rotary knife 2000 of the third exemplary embodiment,except for the configuration of a bearing region 5460 of a blade supportsection 5450 of the annular blade housing 5400. A configuration of abearing race 5466 of a bearing region 5460 of a blade support section5450 of the blade housing 5400 is substantially the same as the bearingrace 4466 of the bearing region 4460 of the blade support section 4450of the blade housing 4400, as described above with respect to theassembled blade—blade housing combination 4500 of the fifth exemplaryembodiment. Specifically, like the bearing race 4466 of the bladehousing 4400, the bearing includes a radial discontinuity or a concaveradial recess 5480 in a back wall 5469 of the bearing race 5466, thatis, a radial discontinuity in a concave, arcuate surface 5466 a formedby the back wall 5469 of the bearing race 5466. The radial recess 5480is within an intermediate portion 5466 c of the arcuate surface 5466 aof the bearing race 5466 and, like the bearing race 5466 is centeredabout a center line or center axis CBH of the blade housing 5400.

For brevity, reference is hereby made to the description of the concavebearing race 4466 of the blade support section 4450 of the blade housing4400 of the fifth exemplary embodiment, as to the structure,configuration, function and advantages of the bearing race 5466 of theblade housing 5400 of the sixth exemplary embodiment. And suchdescription and corresponding drawings of the concave bearing race 4466of the blade support section 4450 of the blade housing 4400 areincorporated herein with respect to the bearing race 5466 of the bladehousing 5400 of the sixth exemplary embodiment. With regard to thestructure, configuration, function and advantages of the remainder ofthe blade housing 5400, reference is hereby made to the description ofthe blade housing 2400 of the third exemplary embodiment and isincorporated herein with respect to the blade housing 5400 of the sixthexemplary embodiment.

As used herein, terms of orientation and/or direction such as front,rear, forward, rearward, distal, proximal, distally, proximally, upper,lower, inward, outward, inwardly, outwardly, horizontal, horizontally,vertical, vertically, axial, radial, longitudinal, axially, radially,longitudinally, etc., are provided for convenience purposes and relategenerally to the orientation shown in the Figures and/or discussed inthe Detailed Description. Such orientation/direction terms are notintended to limit the scope of the present disclosure, this application,and/or the invention or inventions described therein, and/or any of theclaims appended hereto. Further, as used herein, the terms comprise,comprises, and comprising are taken to specify the presence of statedfeatures, elements, integers, steps or components, but do not precludethe presence or addition of one or more other features, elements,integers, steps or components.

What have been described above are examples of the presentdisclosure/invention. It is, of course, not possible to describe everyconceivable combination of components, assemblies, or methodologies forpurposes of describing the present disclosure/invention, but one ofordinary skill in the art will recognize that many further combinationsand permutations of the present disclosure/invention are possible.Accordingly, the present disclosure/invention is intended to embrace allsuch alterations, modifications, and variations that fall within thespirit and scope of the appended claims.

1-35. (canceled)
 36. An annular rotary knife blade for rotation about a central axis of rotation in a power operated rotary knife, the annular rotary knife blade comprising: a body and a blade section extending from the body; the body including a first end and a second end spaced axially from the first end and an inner wall and an outer wall spaced radially from the inner wall, the outer wall of the body including an arcuate surface protruding outwardly with respect to the central axis of rotation, the arcuate surface including an upper region and a lower region, the upper region of the arcuate surface being axially closer to the first end of the body and the lower region of the arcuate surface being axially closer to the second end of the body; the body further including a driven gear having an upper end and an axially spaced apart lower end and comprising a plurality of gear teeth, the plurality of gear teeth including outer surfaces comprising at least a part of the arcuate surface; and the outer wall of the body further including a first bearing surface for rotatably supporting the annular rotary knife blade for rotation about the central axis of rotation, the first bearing surface including an upper bearing face in the upper region of the arcuate surface and a lower bearing face in the lower region of the arcuate surface, the outer surfaces of the plurality of gear teeth comprising at least a part of one of the upper bearing face and the lower bearing face of the first bearing surface.
 37. The annular rotary knife blade of claim 36 wherein the arcuate surface of the outer wall of the body of the annular rotary knife blade, when viewed with respect to a plane parallel to the central axis of rotation of the annular rotary knife blade, defines a constant radius of curvature.
 38. The annular rotary knife blade of claim 36 wherein the upper region of the arcuate surface extends between an upper end portion and an intermediate portion and the lower region of the arcuate surface extends between a lower end portion and the intermediate portion, the upper region and the lower region, when viewed with respect to a plane parallel to the central axis of rotation of the annular rotary knife blade, define a constant radius of curvature.
 39. The annular rotary knife blade of claim 36 wherein the blade section extends from the second end of the body and the arcuate surface of the outer wall of the body is convex radially outward with respect to the central axis of rotation of the annular rotary knife blade.
 40. The annular rotary knife blade of claim 36 wherein the plurality of gear teeth of the driven gear extend axially downwardly from the first end of the body and extending radially through the outer wall of the body, the plurality of gear teeth include outer surfaces comprising at least a part of the upper region of the arcuate surface and the outer surfaces of the plurality of gear teeth comprising at least a part of the upper bearing face of the first bearing surface.
 41. The annular rotary knife blade of claim 36 wherein the outer wall of the body further includes a bearing race that is concave radially inward with respect to the central axis of rotation, the bearing race including an upper region and a lower region, the upper region of the bearing race being axially closer to the first end of the body and the lower region being axially closer to the second end of the body, the outer wall of the body further including a second bearing surface for rotatably supporting the annular rotary knife blade for rotation about the central axis of rotation, the second bearing surface including an upper bearing face in the upper region of the bearing race and a lower bearing face in the lower region of the bearing race.
 42. The annular rotary knife blade of claim 41 wherein the upper region and the lower region of bearing race are arcuate surfaces which, when viewed with respect to a plane parallel to the central axis of rotation of the annular rotary knife blade, define a constant radius of curvature.
 43. The annular rotary knife blade of claim 41 wherein the upper bearing face and the lower bearing face of the first bearing surface and the upper bearing face and the lower bearing face of the second bearing surface are arcuate in axial extent.
 44. An annular rotary knife blade for rotation about a central axis of rotation in a power operated rotary knife, the annular rotary knife blade comprising: a body and a blade section extending from the body; the body including a first end and an axially spaced apart second end and an inner wall and a radially spaced apart outer wall, the outer wall of the body including an arcuate surface protruding outwardly with respect to the central axis of rotation, the arcuate surface including an upper region and a lower region, the upper region of the arcuate surface being axially closer to the first end of the body and the lower region of the arcuate surface being axially closer to the second end of the body; the body further including a driven gear comprising a plurality of gear teeth, the plurality of gear teeth including outer surfaces comprising at least a part of the arcuate surface; and the outer wall of the body further including a first bearing surface for rotatably supporting the annular rotary knife blade for rotation about the central axis of rotation, the first bearing surface including an upper bearing face in the upper region of the arcuate surface and a lower bearing face in the lower region of the arcuate surface.
 45. The annular rotary knife blade of claim 44 wherein the arcuate surface of the outer wall of the body of the annular rotary knife blade, when viewed with respect to a plane parallel to the central axis of rotation of the annular rotary knife blade, defines a constant radius of curvature.
 46. The annular rotary knife blade of claim 44 wherein the outer surfaces of the plurality of gear teeth comprising at least a part of one of the upper bearing face and the lower bearing face of the first bearing surface.
 47. The annular rotary knife blade of claim 44 wherein the blade section extends from the second end of the body and the arcuate surface of the outer wall of the body is convex radially outward with respect to the central axis of rotation of the annular rotary knife blade.
 48. The annular rotary knife blade of claim 44 wherein the plurality of gear teeth of the driven gear extend axially downwardly from the first end of the body and extending radially through the outer wall of the body, the plurality of gear teeth include outer surfaces comprising at least a part of the upper region of the arcuate surface and the outer surfaces of the plurality of gear teeth comprising at least a part of the upper bearing face of the first bearing surface.
 49. The annular rotary knife blade of claim 44 wherein the outer wall of the body further includes a bearing race that is concave radially inward with respect to the central axis of rotation, the bearing race including an upper region and a lower region, the upper region of the bearing race being axially closer to the first end of the body and the lower region being axially closer to the second end of the body, the outer wall of the body further including a second bearing surface for rotatably supporting the annular rotary knife blade for rotation about the central axis of rotation, the second bearing surface including an upper bearing face in the upper region of the bearing race and a lower bearing face in the lower region of the bearing race.
 50. The annular rotary knife blade of claim 49 wherein the upper region and the lower region of bearing race are arcuate surfaces which, when viewed with respect to a plane parallel to the central axis of rotation of the annular rotary knife blade, define a constant radius of curvature.
 51. The annular rotary knife blade of claim 49 wherein the upper bearing face and the lower bearing face of the first bearing surface and the upper bearing face and the lower bearing face of the second bearing surface are arcuate in axial extent.
 52. An annular rotary knife blade for rotation about a central axis of rotation in a power operated rotary knife, the annular rotary knife blade comprising: a body and a blade section extending from the body; the body including a first end and an axially spaced apart second end and an inner wall and a radially spaced apart outer wall, the outer wall of the body including a first surface protruding outwardly with respect to the central axis of rotation, the first surface including an upper region and a lower region, the upper region of the first surface being axially closer to the first end of the body and the lower region of the first surface being axially closer to the second end of the body; the body further including a driven gear comprising a plurality of gear teeth, the plurality of gear teeth including outer surfaces comprising at least a part of the first surface; and the outer wall of the body further including a first bearing surface for rotatably supporting the annular rotary knife blade for rotation about the central axis of rotation, the first bearing surface including an upper bearing face in the upper region of the first surface and a lower bearing face in the lower region of the first surface, the outer surfaces of the plurality of gear teeth comprising at least a part of one of the upper bearing face and the lower bearing face of the first bearing surface.
 53. The annular rotary knife blade of claim 52 wherein the first surface of the outer wall of the body of the annular rotary knife blade is an arcuate surface which, when viewed with respect to a plane parallel to the central axis of rotation of the annular rotary knife blade, defines a constant radius of curvature.
 54. The annular rotary knife blade of claim 52 wherein the upper region of the first surface extends between an upper end portion and an intermediate portion and the lower region of the arcuate surface extends between a lower end portion and the intermediate portion, the upper region and the lower region, when viewed with respect to a plane parallel to the central axis of rotation of the annular rotary knife blade, define a constant radius of curvature and the intermediate portion includes a radial outermost location of the body of the annular rotary knife blade.
 55. The annular rotary knife blade of claim 52 wherein the blade section extends from the second end of the body and the first surface of the outer wall of the body is convex radially outward with respect to the central axis of rotation of the annular rotary knife blade.
 56. The annular rotary knife blade of claim 52 wherein the plurality of gear teeth of the driven gear extend axially downwardly from the first end of the body and extending radially through the outer wall of the body, the plurality of gear teeth include outer surfaces comprising at least a part of the upper region of the first surface and the outer surfaces of the plurality of gear teeth comprising at least a part of the upper bearing face of the first bearing surface.
 57. The annular rotary knife blade of claim 52 wherein the outer wall of the body further includes a bearing race that is concave radially inward with respect to the central axis of rotation, the bearing race including an upper region and a lower region, the upper region of the bearing race being axially closer to the first end of the body and the lower region being axially closer to the second end of the body, the outer wall of the body further including a second bearing surface for rotatably supporting the annular rotary knife blade for rotation about the central axis of rotation, the second bearing surface including an upper bearing face in the upper region of the bearing race and a lower bearing face in the lower region of the bearing race.
 58. The annular rotary knife blade of claim 57 wherein the upper region and the lower region of bearing race are arcuate surfaces which, when viewed with respect to a plane parallel to the central axis of rotation of the annular rotary knife blade, define a constant radius of curvature.
 59. The annular rotary knife blade of claim 57 wherein the upper bearing face and the lower bearing face of the first bearing surface and the upper bearing face and the lower bearing face of the second bearing surface are arcuate in axial extent. 